My Twin Stepsisters

I was in the home gym. The room smelled like rubber mats and metal. Sweat ran down my chest. Dad and my stepmom were out of town again for another business trip. Four days, at least. The house felt quiet without them.

I was in the middle of my set when the gym door swung open hard.

Ella walked in like she owned the place. Black sports bra, tight shorts that hugged her thick ass and showed the line of her hips. Big tits barely held in by the sports bra. She looked at me with that cold, bitter face she always wore around me.

“You’re still using the gym?” she said. Her voice was sharp. “Some of us actually need it.”

I set the weights down. “I’ve been here twenty minutes. The room’s big enough for both of us.”

“Whatever.” She dropped her bag on the floor and went straight to the squat rack. “Just stay out of my way.”

I felt my jaw tighten. Three weeks of this same attitude and I was already sick of it. Still, my eyes kept drifting. The way her ass filled those shorts when she bent to load the bar. The heavy shape of her tits when she stood up. The smooth line of her stomach disappearing into her waistband. I couldn’t help it.

She caught me looking.

“What the hell are you staring at?” she snapped. “God, you’re such a pervert.”

“I wasn’t....”

“Yes you were. Eyes up here, stepbrother.” She said the word like it tasted bad. “Or better yet, don’t look at me at all.”

I clenched my teeth and turned back to the cables. My shoulders were tense now. I really couldn’t stand her sometimes.

A few minutes later the door opened again, quieter this time.

Emma stepped in. Same face as her sister, same body, but everything about her felt different. She wore a light pink tank top and soft yoga pants. Her smile was small and a little shy.

“Hey, Lucas,” she said.

“Hey, Emma.”

Ella made a short humph sound from the squat rack, like the simple greeting annoyed her.

Emma walked over to the open mat area and rolled out her yoga mat. She started stretching, slow and careful. I tried not to watch the way her chest moved when she reached forward, or how the yoga pants clung to her ass when she bent.

The twins had been living here for three weeks now. Ella and Emma. Same face. Same body. Big tits, thick asses, the kind that made every pair of shorts look too small. Most people still mixed them up. I never did.

It wasn’t the faces. It was everything else. The way they walked. The way they talked. The way they looked at me or didn’t.

Ella finished her last set with a loud clang of the bar. She grabbed her towel and water bottle, then looked at her sister.

“Emma. Be careful around him.” Her voice was cold. “He’s been staring the whole time.”

She turned to me on her way out. Her eyes were hard.

“Pervert.”

The door shut behind her. I let out a long breath. That girl got under my skin like nothing else.

Emma stayed on her mat for a moment, then looked over at me. Her voice was soft.

"Sorry about her. Ella’s....Ella.”

Even the way she said her sister’s name was different. Softer. Almost protective.

“I’ve noticed.”

She looked at me for half a second. Her eyes were darker than Ella’s. Softer too. They dropped to my chest, then away again. That was pure Emma. Ella would have held the stare until I looked away first.

“She doesn’t mean half the things she says,” Emma said quietly.

“I think she means every word.”

“Ella’s just....frustrated. We never had a man in the house before. No siblings. No father around. It’s been only us and Mom for a long time. She doesn’t know how to act sometimes. But she’s a good girl, really.”

I wiped my face with my shirt. “It’s fine. I don’t mind.”

Emma nodded. She hesitated, fingers playing with the edge of her mat. Her cheeks looked a little pink.

“Um....Lucas?”

“Yeah?”

“Could you..maybe guide me a little? With the weights, I mean. I’ve only ever done yoga. I want to try something different. If you’re not busy.”

I looked at her. Soft eyes. Nervous smile. Completely different from the sister who just walked out calling me a pervert.

“Sure,” I said. “I can show you a few things.”

She smiled wider, still a bit shy, and stood up from her mat.

“Thank you.”

I started her with something simple.

“We’ll do goblet squats first,” I said, picking up a light dumbbell. “Hold it against your chest. Feet a little wider than your shoulders. Sit back like you’re about to sit in a chair.”

Emma nodded and took the weight. Her fingers brushed mine for a second. Soft. Warm. She held the dumbbell against her chest the way I showed her. The pink tank top stretched tight across her tits. I could see the shape of them clearly every time she breathed.

“Like this?” she asked.

“Yeah. Now go down slow.”

She lowered herself. The yoga pants clung to her thick thighs and ass. When she reached the bottom, the fabric stretched even tighter. I stood a little to the side, watching her form, but my eyes kept dropping.

Fuck. She looked too good.

“Up,” I said. My voice came out rougher than I wanted.

She stood. Did it again. And again. Every time she went down, her ass pushed out. Full. Round. Soft-looking. The thin material of her pants left almost nothing to the imagination. I forced myself to look at her knees, her back, anything else. It didn’t help much.

After a few reps she slowed down.

“Is my form okay?” she asked, a little out of breath.

“Almost. You’re leaning forward too much. Here....”

I stepped behind her before I could stop myself. My hands went to her hips. The second I touched her, I felt how warm she was through the thin fabric. My fingers sank in just a little.

“Push your hips back more,” I said. “Keep your chest up.”

She did what I said. As she lowered herself, her ass came back and pressed right against the front of my shorts. Soft. Full. I felt the heat of her through both layers of clothing. My cock twitched hard.

We both froze for a second.

“Sorry,” she said quickly, standing up.

“Yeah. My bad.” I stepped back, but not as far as I should have.

We kept going. The next few reps were the same. Every time she squatted, her ass brushed me. At first we both mumbled sorry. Then the apologies got quieter. Then they stopped.

I stayed behind her, hands lightly on her hips, telling myself I was only helping with her form. But my cock was getting harder with every rep. When she went down, the soft curve of her ass pressed against me. When she stood, it dragged slowly up the length of my dick. The fabric of my shorts was thin. So were her yoga pants. I could feel everything.

My mind was a mess.

She’s your stepsister. You barely know her. Ella already thinks you’re a pervert. Stop.

But I didn’t stop. My hands stayed on her hips. My body stayed close. And when she went down again, I didn’t pull my hips back. I let her ass press fully against my hard cock. The pressure felt too good. I held it there a second longer than I needed to.

Emma’s breathing changed. It got heavier. She didn’t say anything. She didn’t move away either.

We switched to Romanian deadlifts next. I stood behind her again, closer this time. When she hinged forward, her ass pushed straight back into me. My cock slid right between her cheeks, trapped by the thin clothes. I could feel the soft heat of her. The shape of her. My hands tightened on her hips without meaning to.

She stayed bent over a little longer than the form needed.

I didn’t tell her to stand up right away.

My thoughts were filthy now. I kept imagining pulling those yoga pants down, seeing that thick ass bare, pushing my cock between those soft cheeks for real. I hated how badly I wanted it. I hated that I was still hard and still standing this close.

“Lucas…” she said quietly. Her voice sounded different. Softer. Almost shaky.

“Yeah?”

“Is this… right?”

She pushed her ass back a little more. Deliberate. Slow. My cock throbbed hard against her. I could feel the exact place where the head pressed between her cheeks. The thin fabric did almost nothing to hide how hard I was.

I should have stepped away. I didn’t.

“Yeah,” I said, voice low. “That’s fine.”

She moved again. Just a small roll of her hips. Up, then down. Dragging the soft weight of her ass along my cock. My fingers dug into her hips. A quiet breath left her mouth. She did it again. Slower this time.

My mind went blank for a second. All I could feel was how soft she was, how warm, how perfectly she fit against me. My cock was leaking now. I was sure she could feel how hard I was. She had to.

She kept moving. Tiny, careful motions. Like she was testing something. Or like she couldn’t stop herself either.

I leaned forward just a little. My chest almost touched her back. I could smell her hair. Clean sweat and something sweet. My hands slid a bit lower on her hips. My thumbs pressed into the soft flesh near the top of her ass.

Then her balance slipped.

It happened fast. She wobbled on the way up from the hinge. A small surprised sound left her throat. I reacted without thinking. My arms wrapped around her from behind to keep her from falling.

One of my hands landed too high.

My palm closed over the soft, heavy shape of her breast. Full. Warm. The thin tank top did nothing to hide how soft she felt in my hand. My fingers sank into the soft flesh without meaning to.

I froze.

She froze too.

I didn’t move my hand away.

She didn’t say anything.

Her back stayed pressed against my chest. Her ass was still fully seated against my hard cock. And my hand stayed right there, holding one of her soft, big tits like it belonged there. I could feel her nipple under my palm, already a little hard. Her breathing turned heavier against my arm.

Neither of us spoke.

Then, slowly, she shifted her hips. Not away. Back. Grinding the soft weight of her ass against my cock in a slow, deliberate drag.

Up.

Down.

I could feel everything. The heat of her. The soft give of her cheeks. The way my cock sat perfectly in the middle. My hand stayed on her breast. I didn’t squeeze. I just held it. Feeling the soft weight of it in my palm. My mind was screaming at me to let go, but my body refused.

Emma’s breath hitched. She did it again. A slow roll of her hips. Then another. The friction through the thin clothes was almost too much. My cock was rock hard and leaking, and she could feel every bit of it. She wasn’t pulling away. She was pressing back. And she still hadn’t said a word about my hand on her tit.

I closed my eyes for a second. All I could think about was how soft she felt in my hand. How easy it would be to slide my other hand under her tank top. How badly I wanted to pull her pants down and feel her skin against me for real. My stepsister. The quiet one. The one who smiled at me.

I was so fucked.

She kept moving. Small, slow grinds. Her ass rubbing up and down the length of my cock. Her breathing had turned into soft, quiet pants. My hand stayed on her breast, thumb brushing the side of it without meaning to. I was grinding back against her now. Not hard. Just enough to feel more of her.

Then the gym door opened.

Both of us froze.

Ella stood in the doorway.