What I Discovered in My Twin Sister’s Panties

Like good twins, during childhood and adolescence we fought all the time. But now, as adults, we don’t. Quite the opposite, really: we team up in everything. We almost have no secrets between us. Almost.

Our house is huge. Some architects would say it’s disorganized or badly designed, but for us it’s perfect. My parents have a gigantic bedroom with two walk-in closets and a bathroom where my mother had a shower installed with two water outlets. It’s almost the size of a living room.

Our individual rooms are smaller, and we share a bathroom between the two of us. Sofía’s door and mine face each other. If you go in through mine, the shower with its fixed glass screen and the sink are on the left; the toilet is on the right. Through my sister’s door it’s the other way around. Seated on the throne, you can perfectly see what’s happening under the water. Sometimes the glass fogs up.

The best part is that we still have the room we shared as kids: the two beds facing each other, the bedside tables, and the old posters stuck to the wall.

***

Monday. The night before, our parents had left on their trip for their twentieth wedding anniversary. A week at an all-inclusive in the Caribbean. I’m going to skip the thousand talks, sermons, and warnings they left us with for staying home alone.

We were both on university break, but I had exams to take. As always.

Close to eight in the morning, I heard Sofía moving around in the bathroom. A sign the day was starting.

“Sofi! Are you going to be long?”

In response, I got the sound of the shower water. Knowing that could last at least forty minutes, I got up. I had quite the erection, the result of a brutal need to piss. I sleep in loose boxer briefs, and with my dick hard, it simply sticks out through the opening in front.

“Excuse me! I’m going to the bathroom, I can’t hold it.”

“Damián! Do you always have to come in when I’m showering?”

I ignored her, as I do every morning, and went straight to the toilet. It was hard to empty my bladder with how stiff my cock stayed.

“Shake it well, and if a drop fell outside, clean it up.”

I didn’t even look at her, much less answer. In the morning I’m not up for talking, and even less for complaints. Out of decency I never looked at her in the shower. But something caught my eye: there was a pair of panties thrown on the floor and the crotch was all shiny. I’d lived my whole life with my sister’s panties, thongs, and boyshorts, almost always tossed in the bathroom. Some were stained, but this one was wet with arousal. It shocked me the way it used to when I was a teenager.

What could have led her to leave the panties like that? They were plain boyshorts, cotton, the kind she wore every day. The night before, after coming back from the airport, we ate dinner, chatted, and went to bed. Thinking about that, I got dressed, went downstairs, and prepared breakfast for both of us.

Coffee, toast, and orange juice. I sat at the high counter waiting for her. When she arrived, I was surprised: she was dressed in sleep clothes. A tank top with cartoon characters and shorts. Under the tank top it was obvious she wasn’t wearing a bra; her breasts, pear-shaped, were moving freely. The straps were long, and when she bent down to move the stool, I saw the whole of one breast and part of the pink areola crowning it.

“What did you make for breakfast?”

“The same as always. Why would I change?”

“Bro, it’s a special week. Mom and Dad aren’t here, we’re on vacation, and we’ve got the whole house to ourselves. Have you thought about what we can do? And the secrets we can find?”

I didn’t recognize her. Why was she so excited about staying home and looking for “secrets”?

“I still have to study for exams, and I don’t know what secrets you want to find here.”

“Let’s make a deal: I help you study, and you follow me in the search for unknown treasures inside the house.”

She held out her pinky, looking to seal the pact. I agreed, mostly because in the morning I don’t feel like arguing. I hooked my pinky with hers.

“Are you planning to go out? Because I decided last night I’m not crossing the front door. I’m spending the whole week inside and I’m barely going to use my phone. So you’re going to see me in pajamas all the time.”

“Someone’s going to have to run errands and bring food.”

“We have everything. The freezer is full.”

She grabbed a notebook from the kitchen and started a list titled “a week alone at home.” The first three items: enjoy ourselves, rest, sleep like when we were kids. Then, while swirling her coffee cup, she added: look for hidden treasures, play house. The notebook was in the middle, with the clear intention that I could read it.

“Study?”

“Fine, okay.”

She added it much lower down, outside the previous order.

***

I went up to my room after breakfast and went into the bathroom to look for the panties. They weren’t on the floor. I went to the laundry basket we share. I was aroused as I hadn’t been in years by my sister’s underwear.

I found them: a black cotton pair of panties, wide, still rolled in at the sides from having been tugged down with two hands from the hips. In the center, a shiny stain. I brought them to my nose and inhaled deeply. What an exciting scent. There’s no other smell as aphrodisiac as that. I was tempted to run my tongue over them. Had she masturbated with the panties on?

What I was doing wasn’t right. She was my sister. We shared everything and loved each other unconditionally. I couldn’t betray her like this. There were no two options: it was wrong.

I pulled down my shorts and boxer briefs. My cock sprang up like a stiff branch. I was going to give myself a quick handjob. I’d surely finish in no time.

But I imagined her touching herself over her clothes, rubbing her clit with fervor. I’m going to stop thinking of her like this, I told myself. My hand started sliding up and down my dick, exposing the swollen glans. She’s my sister, it’s forbidden by every rule I know. I stuck out my tongue and ran it over the full width of the stain.

I tasted it while imagining I was eating her soaked pussy. The first spurts of cum hit the shower screen glass, above my waist. The orgasm built quickly and a wave of pleasure ran through my whole body. I ejaculated three more times. All the cum stuck to the glass.

I left the panties where they were, walked to the sink, put my flaccid cock into the basin, and washed the glans well. I barely had time to pull my clothes back up when Sofía knocked from her door and came in.

“Bro, I recommend you get out because this is about to get ugly.”

She lowered the toilet lid, turned her back to me, and grabbed the sides of my shorts. She froze for a second before pulling them down. She looked at me:

“Are you planning to stay?”

I left. I closed my door and went downstairs to the living room. I set up my laptop and a book to study when I remembered I’d left all the cum on the glass. I cursed inwardly. This is the last time I do something like this, I thought.

***

Sofía arrived and sat next to me. We looked into each other’s eyes for a second. I knew she had seen the cum. She also knew I had jerked off with her underwear.

“Are we going to talk?”

“What do you want to talk about?”

“About what happened this morning.”

“I’ve known for years that you jerk off in the bathroom, Damián. You know I touch myself in my room. What else do we need to talk about?”

“Sorry, I didn’t want you to find everything… dirty.”

“I also didn’t exactly intend for you to find my panties all… wet. Forgive me.”

A smile began to spread across her face and I couldn’t hold back my laughter. Conversations with her were always like that: straightforward, no lies, no problems, and they always started with apologies. That’s why we got along so well.

Then began the conversation that would change the whole week.

“Could it be we need to set new rules for these days?”

“What are you getting at, Sofi?”

“Let’s start with the list. Enjoy is the first item. I’d love for us to do it without inhibitions, without having to cover everything up. It’s so boring to leave everything as it was after… enjoying ourselves.”

“Well, I don’t jerk off that much, so it seems fine to me on that front.”

She looked at me with a face that said, “I know you, you massive wanker.” We laughed out loud. You can’t lie to your twin, the one you share a bathroom and basically everything with.

“Does any place in the house count, at any time?”

“Yes.”

Her short, blunt answer surprised me. Had she already thought it through?

“Does using ‘things’ count?”

“How?”

“The internet, for example.”

“Ah, I thought you were going to say your sister’s underwear.”

I blushed. She joked as if it were natural, and I couldn’t stop thinking about how wrong what I’d done was.

“I don’t think it’s wrong for you to use any ‘thing’ that helps with the first item on the list: enjoy yourselves.”

We looked into each other’s eyes. We both knew we were defining an armed peace. What wasn’t forbidden was allowed.

“Any other rule?”

“No, for now. If anything comes up, I’ll let you know. I’m going to the old room.”

***

I studied all morning and then went to look for her. The childhood room had the two beds pushed against the side walls. A window with a long ledge at the back, and the old posters: soccer players on my side, music bands on hers.

When I got there, I found her asleep in the fetal position. One breast had come completely out of her tank top. How pretty she was with her pink nipple. I pulled her shorts up a little to leave her ass exposed, careful not to wake her. The curve was gorgeous. She was wearing a very small flesh-colored thong, a little old and stretched out.

I stepped back to look at her and enjoy the view. I got aroused little by little, remembering the scent from the morning. My cock woke up on its own, without asking permission.

I sat on my old bed, leaned my back against the wall, pulled down my Bermuda shorts and boxer briefs, letting them fall between the beds. I started touching myself slowly, pulling the skin down until all the glans was exposed and then hiding it again. A slow, tight up-and-down.

Sofía woke up. I imagine she felt my presence.

“How long have you been there… watching me?”

“I just got here.”

“I see you’re already putting the new rules to use.”

She said it smiling and sat up. She sat facing me, just like me, without adjusting her tank top.

“Many years ago, in these same beds, we showed each other our private parts. Later we bragged to friends about having seen someone completely naked. Is it time to do it again, but so we can say, ‘I saw someone masturbate to orgasm’?”

“I don’t see why not.”

She took off her shorts and kept the thong on. She began running two fingers over the fabric, right at the height of her clit. She bit her lower lip and half-closed her eyes. I had to stop touching myself: if I kept going like that, I’d come in an instant. She lifted one breast to her mouth and let a thread of saliva fall onto the nipple.

“Ahhh…” I let out.

With her whole palm she pressed her entire crotch over the thong. She lifted her ass to push it forward a little more. Her legs were wide open.

I squeezed the shaft of my cock, rock-hard and hot. I covered the glans with the skin. With my other hand I took saliva, pulled all the skin back, leaving the purple head bare, and let the spit fall on top of it. All wet, shiny. It was easier to touch myself like that.

She pulled the thong aside and I saw her pink pussy, intense with arousal. The small lips couldn’t contain the shiny bud. She shifted the garment to one side of her ass and positioned herself so I could see everything. She started rubbing harder. I saw drops of fluid running from inside to out.

“Ahhh, yes!” she sighed.

She intensified the rhythm and the pressure on her clit. She looked at me while I jerked off. Until her face changed: she had reached orgasm. She had to close her knees and bring together her trembling legs. She let herself fall to one side with her eyes closed.

Seeing her come drove me crazy. I started increasing the speed, I was on the verge of ejaculating and soaking the floor. But two seconds after collapsing, she shot upright and ran out. She left only the shorts on the floor by the bed.

I stood there in shock, my cock still rock-hard. When I got to her room, the door was closed.

“Sofi, are you okay? Sorry! Are you okay?”

“No…”

The voice from the other side was fragile.

“I don’t want to talk right now. Forgive me too.”

“If you let me in, we’ll fix it like always.”

“No, don’t come in.”

I went to my room and left her alone. I needed to think too. What we were doing wasn’t right. And everything had happened too fast.

***

I couldn’t stay locked up. I went downstairs to cook. After a while I told her the food was ready. I had made a green salad with half a frozen pizza. One of her favorite meals.

She appeared in the kitchen the same way she’d left: in a thong and tank top. I thought she might have dressed or changed her attitude, but no.

Trying not to draw attention, I took the salad and pizza to the table.

“Damián, stop for a second. Let’s talk about what happened.”

“What do you want to talk about? What we did was wrong. I apologized. That’s it.”

“I enjoyed it a lot.”

The comment left me speechless.

“It’s been ages since I had an orgasm that intense from a handjob. I owe that to you and to him,” she said, pointing at my crotch.

“I wish I could say the same.”

“Since yesterday I’d been thinking about this. Kink gets me insanely turned on, and it excites me way too much. It’s wrong, but my crotch gets wet just thinking about it. Fair’s fair: before lunch, I owe you something.”

She pulled down her thong and handed it to me. In one leap she climbed onto the kitchen counter, rested her heels on the edge, and opened her legs.

There, in front of me, I saw her pussy opening like a flower. Pinkish, with the little lips still shiny from her own fluids. You could see the opening below the clit, which barely peeked out between the folds. It was ready to receive everything. She caressed herself a little, opened wider, spread the lips apart.

“Do you want me to masturbate here in the kitchen, with you like this?”

“We already agreed: any place and any thing.”

I pulled down my clothes. Once again my hard cock pointed upward. I started touching myself.

“You’re going to smell my thong. Just like yesterday’s panties, it’s soaked.”

I brought it to my face and smelled it. Still damp. The scent was intense. I didn’t dare run my tongue over it.

I gave myself a hard handjob, a brutal up-and-down. I felt the ejaculation coming. I let go of my cock.

“I’m going to cum.”

Without touching myself, I came fiercely. I watched it pulse and spurt semen. The orgasm made me bend a little. The amount of cum was enormous. I felt a pleasure unlike anything I’d ever felt from a handjob.

I looked at her face for the first time.

“You’re right. I’d never enjoyed a handjob that much before.”

She smiled and looked at her leg, where a little of my cum was running down. I hadn’t noticed, but I’d dirtied the drawers of the counter and parts of her legs. She extended one finger, scooped up a bit of semen, looked at me again, and brought it to her mouth.

“Warm is better. Cold isn’t the same.”

Shocked by the action and the statement, I blushed. The fears and doubts came back.

“I need to think.”

I grabbed a plate with two slices of pizza and went to my room. I didn’t come out until night.