I Taught My Sister-in-Law What Her Boyfriend Would Never Forget

My husband’s sister had just turned twenty, and until then she had lived for two things: athletics and her studies. Good grades, a place in the physical therapy program, and a body the track had sculpted without her realizing what it provoked. Her name is Noa, although that isn’t her real name, and she had the firmest legs I’d seen in a long time.

I don’t say that just because of her age. I say it because of the hours of training, the defined calves, and that narrow waist you could make out whenever she came back from running. I watched her leave the house in shorts that revealed the beginning of her thigh, and something in me kept looking longer than it should. If only I could put my tongue between those legs and eat her pussy until she screamed, I thought, and then I scolded myself for thinking it.

One Thursday I ran into her in the street, near the market in Valencia where I did my shopping. After some pointless small talk, she asked me to go clothes shopping with her. I happily agreed. We took the metro to a shopping center on the outskirts and started wandering through the stores without hurrying. Shopping relaxes me, while she seemed distracted by something else.

First we looked at dresses for going out. Then, almost without meaning to, we ended up in front of a lingerie shop window.

—You’re meeting someone, aren’t you? —I asked.

—Yes… —she replied, biting her lip—. I’m really nervous.

—Why? What are you nervous about?

—Because we’ve already seen each other several times and…

—And you’ve fucked.

—No. That’s the problem. We haven’t fucked yet.

—I don’t see anything wrong with that. When you feel like it, you will.

—That’s exactly the problem, Marina.

—Noa, I don’t understand.

—I’ve never fucked. With anyone.

I stopped dead in the middle of the corridor. I looked at her, searching for a smile that would tell me she was joking, but there wasn’t one.

—I’ve done a little fooling around —she went on, lowering her voice—, but when it came down to it, I got embarrassed and stopped. I’ve never sucked a cock, and I’ve never let anyone put it inside me. This time I don’t want to stop. I want him to fuck me properly.

—So what’s holding you back?

—The fact that I don’t even know how to hold a man’s cock. I don’t know anything. And I don’t want my first time to be a disaster in front of him.

I let out a laugh I couldn’t contain, and it made her blush all the way to her ears. I took her by the arm and told her to calm down, that we’d all been there at some point. Though, to be honest, I’d been sucking cocks and spreading my legs since I was considerably younger than she was.

—I’m your older sister-in-law, Noa. I can help you. But I need to know one thing: are you serious about this guy?

—As serious as anything can be after six months.

—Six months without touching each other? Poor man. His balls must be purple.

—I know. He’s waited with the patience of a saint because I told him I was a virgin and wanted my first time to be special. That’s why I’m terrified of making a fool of myself. I don’t want to remember my first time as a failure.

I thought about it a moment longer than I should have, and then the outrageous idea slipped out.

—I’ll teach you.

—Teach me what?

—This. How to suck, how to fuck, how to come and how to make him come. Everything you need to know so that you enjoy that night and so does he.

—I’m sick of theory, Marina. You know I’m a good student. I’ve asked the internet everything there is to ask.

—I’m not talking about theory. I’m talking about practice. With a trusted friend, with a real cock in your mouth. But this stays between us, and not a word to your brother.

***

—I don’t want to cheat on my boyfriend —she said suddenly, coming to an abrupt stop.

—It isn’t cheating. It’s practice.

—What do you mean, practice! It’s textbook infidelity.

—Look, if you want to start arguing about morality, we can —I told her—. But I don’t think anything will happen just because you learn to suck him properly and no one ever finds out. My friend is discretion personified.

She fell silent, thinking it over. I knew that look: it was the same one she wore before a difficult exam she knew she was going to pass.

—All right —she finally gave in—. But if I feel strange, I’ll stop and leave. Deal?

—You’re not going to stop. I’m telling you. Once you have his hard cock in your hand, you won’t want to let go.

In less than a day I had everything arranged. My friend’s apartment, a perfect alibi—another afternoon of shopping between sisters-in-law—and Noa waiting with a mixture of fear and curiosity you could almost touch. We arrived at the building, went upstairs, and Adrián opened the door with that calm of his, the calm of someone who’s never surprised by anything. He was a gym buddy I’d already had my way with; from experience, I knew he was thick, long, and could take anything you gave him. Noa would be in good hands with him.

—Noa, this is Adrián. We trust each other, and he’ll treat you with all the affection in the world. You’ll see.

—Nice to meet you —she said, giving him two kisses.

—Nice to meet you —he replied.

—Let’s get to the point. This girl has a date and doesn’t even know where to start. As I told you, you don’t mind serving as her model, right?

—Not at all —he smiled—. She can use my cock as much as she wants. It’s all hers.

—Noa, come here. Get on your knees beside me.

My sister-in-law settled onto the floor, one hand on Adrián’s leg and the other trembling slightly. I positioned myself on his other side, close by, so I could guide her without making her guess.

—First, sweetheart, run your hand over his pants. Slowly. Just to get familiar with the bulge, so his cock can start getting hard on its own and everything else follows naturally.

I placed my hand over hers and moved it just a couple of times. Beneath the denim, Adrián’s package began to grow, stretching long along his thigh. Noa’s eyes widened when she felt it pulsing beneath her fingers.

—Fuck… it moves —she whispered.

—Of course it moves. It’s alive. Touch it more, squeeze it. Run over the whole thing through the fabric until it’s hard as a rock.

She continued on her own, with an awkward caress that gradually became more confident, feeling the length of his cock from base to tip, measuring it with her hand.

—Feel it? Now that it’s firmer, unbutton him and pull it down. It’s the most boring part, but men like not having to do anything.

Noa obeyed. She undid his button, lowered the zipper, and pulled his jeans down to his knees. Adrián’s black briefs held such a pronounced bulge that the tip poked above the waistband, red and shiny. With his briefs still on, I brought her face closer so she could smell him, so she could scatter kisses over the fabric.

—Smell him, darling. Put your nose in there. That hot-man smell is what you have to learn to like. Now nibble at it through the fabric, without squeezing, just to tease him.

Noa buried her face between Adrián’s legs and inhaled deeply. She ran her lips along the length of his covered cock, gently bit the tip poking out, and sucked the fabric until she left a dark patch of saliva. By then she had lost almost all her shyness and kissed him with a devotion I hadn’t expected from someone who had never done it before.

She finished pulling down his briefs herself, and Adrián’s cock sprang out in front of her face, thick and veined, the tip swollen and a transparent drop appearing at the little opening. She stared at it silently, mouth slightly open, waiting for instructions. Adrián watched her in silence, without rushing her, legs spread and balls hanging heavily between his thighs.

—Ready for your first real cock? —I asked in her ear—. Today you’re getting rid of your curiosity and leaving here knowing how to suck like a whore.

—Ready, sis-in-law.

—Let’s begin. I know you’ll want to go straight to swallowing it, but that’s not how it’s done. Relax. Take it at the base with one hand and gently massage his balls with the other. You’ll feel it get even thicker.

Noa wrapped her fingers around his cock and felt its hot weight in her palm. She squeezed gently, and a transparent thread trickled over the glans. With her other hand, cupped, she took Adrián’s testicles and weighed them as if measuring a piece of fruit. She learned quickly. She tried one amount of pressure, then another, watching what made Adrián smile and what made him close his eyes. She moved her fist up and down, awkwardly at first, then more fluidly, pulling back the foreskin and fully exposing that bright red head.

—Bring your nose closer, smell him, take your time —I instructed—. Stick out your tongue underneath and lick from the balls to the tip. One long lick, without fear. Hurrying ruins everything.

She lowered her face slowly, breathing in the smell of skin and sweat, and stuck out her tongue. She began down at the root of the testicles and moved upward, dragging the tip along the entire underside of his cock, following the thick vein running across it, until she reached the glans. Adrián let out a hoarse moan. She repeated the lick, then another, and before I knew it she was kissing his entire cock with a tenderness that didn’t seem like a first time, but like the tenderness of someone who had spent her whole life wanting to eat one.

—His balls too. Put them in your mouth one at a time, carefully. Men go crazy for it.

Noa opened her lips and sucked in one of his testicles, letting it roll around in her mouth while her tongue danced around it. Adrián threw his head back and didn’t say another word all afternoon. I gave Noa little taps on her hair to set the rhythm, so she wouldn’t rush. With my own hand, I taught her to masturbate his cock while she sucked his balls, coordinating both movements.

—That’s it. Now move up to the tip. Short strokes of your tongue, as if you had to clean something sweet. Concentrate on the frenulum, that area beneath the head. That’s where everything will start trembling.

She ran the tip of her tongue over it once, twice, and on the third time she closed her lips around the glans and dared to go further. She tried to take him deep in one sudden movement, swallowing half the cock at once, and gagged, coughing, her eyes watering and a thread of saliva hanging from her chin.

—See? Don’t go at your own pace. Listen to me, slowly. Stay up top, playing with the head, until your throat gets used to it. It’ll ask for the rest all by itself.

Noa recovered immediately. Tongue circling the glans, a sucking kiss, another circle, each time with more saliva and more sound. Suck, suck, suck—the noise filled the room. She spat on his cock to lubricate it, gripped it with both hands, and twisted it as if she’d learned the lesson on the spot. I could feel my own breathing speeding up, could feel my panties soaking through as I watched her, and I had to remind myself that the man I slept beside every night was the brother of the girl next to me. I held myself back as best I could, biting down on the urge to pull down my sister-in-law’s pants and put my tongue in her pussy while she kept sucking.

When I saw that she was getting too enthusiastic, I asked her to take it out for a moment and tested her endurance carefully, step by step. I held the back of her head firmly and lowered it onto the cock, first halfway, then a little farther. At first her stomach nearly turned when the tip brushed her throat; after the second gag she tried breathing through her nose; after the third she swallowed the entire cock until her nose touched Adrián’s pubis, and endured it without blinking, her throat contracting around that thick shaft.

—Perfect. Now take it with your mouth relaxed, your tongue loose, slowly and as deeply as you can. When you reach the bottom, close your lips and come back up, dragging everything along and leaving it as dry as possible. That suction is what drives anyone crazy.

Noa placed one hand at the base and the other on Adrián’s thigh. She began a slow rocking motion, taking him all the way in and rising with her lips tight around his cock, sucking so hard that her cheeks hollowed inward. Every time she came up, the cock emerged from her mouth shining with saliva; every time she went down, a wet gurgle sounded from the back of her throat. She loved every moment of it, I could tell, and without realizing it she kept running out of air from concentrating so hard.

A sudden gasp forced her to stop so she wouldn’t choke. She pulled her head back sharply, a long strand of saliva connecting her mouth to the tip of his cock, and looked at me with reddened eyes, a runny nose, smeared mascara, and glossy lips. But she was happy. Radiant.

—I love it —she panted—. Fuck, Marina, I love sucking cock.

—I told you. Keep going, student.

I nodded, and she returned to it without needing another word. Now she ate him more fiercely, her left hand moving up and down the base in time with her mouth, her right massaging his balls. The student was on her own now. When she rested for a few seconds, she repeated the kisses along the full length, licks over the glans, circles with her tongue around the frenulum. She murmured, almost purred with pleasure, and those wet sounds mingled with Adrián’s ragged breathing as he clenched his fists against the sofa and tightened his thighs.

When I felt he was close, I asked her to stop and go back down with her tongue.

—If he comes now, he won’t have enjoyed even half of it —I explained—. It’s not about him unloading in the first minute; it’s about lengthening the journey until he begs you. For him and for you. Rest, go back to his balls, keep him hot without letting him come.

That was the only pause she took. Noa licked his testicles, blew over his dripping cock, gripped it in her hand, and gently fanned it against her cheeks, playing with it. After that there was no way to stop either of them. She cleaned all the saliva away with her tongue and swallowed him to the bottom again, this time without gagging, with a control I found hard to believe in someone who, an hour earlier, hadn’t even known how to hold it. She moved up and down with a steady rhythm, pulling him out completely to lick the tip, then swallowing him again all the way to the balls.

Adrián warned with a growl that he was at the limit. His thighs tensed, his hands dug into the sofa, and his balls drew up tight against his body. I placed a hand on the back of Noa’s head, held her with his cock inside her mouth, brought my lips to her ear, and whispered:

—Hold on. Keep it inside or swallow every last drop. Do that and you’ll be perfect.

The sounds suddenly intensified, and he could no longer hold back. He drew breath, there was one second of absolute silence, and then he let go. The cock jerked in Noa’s mouth and released a thick jet of semen against her palate. Another. Then another. My sister-in-law’s eyes flew wide with surprise as she felt her mouth fill with hot milk, and she pulled her face away, closing her lips with effort. One last spurt stained her chin and dripped down to her cleavage. She wasn’t used to the taste. She didn’t exactly enjoy having all that cum pooled in her mouth.

Without thinking, I pressed my lips to hers to seal them shut and pushed gently with my tongue, helping her swallow. I kissed her deeply, tasting Adrián’s warm semen that we shared between our two mouths. She did it. She swallowed in one gulp, with a muffled moan, then opened her mouth and let me check that nothing remained, giving her the longest kiss of her life in the process. With my tongue I cleaned the drop hanging from her chin and passed it to hers. We continued like that, slowly, until there was nothing left but one final brush of lips. That was how we signed off on her first practical lesson.

—You’re certified now —I told her, laughing—. You know how to suck it, you know how to swallow an entire load, and you know how to take it all the way down. Your boyfriend is going to be the happiest man on earth when he has you on your knees.

Her eyes shone with sheer pride. She wiped her face with the back of her hand, fixed her hair, which was stuck down with sweat, and hugged me in the way people hug when someone has lifted a weight from their shoulders. Then she hugged Adrián, who was still sprawled on the sofa, his glistening cock hanging between his legs.

Three days later she sent me a single message: “I passed with flying colors. I swallowed the whole thing.” She didn’t need to add anything else.