Wrong room, right sister

So I’m m (27) and my partner is f (26), we’ve been dating for about a year and I’ve been slowly getting to know her family. Especially her identical twin. We often have family get togethers during the weekend.

I still can’t believe that happened honestly.

We were all drunk at my girlfriend’s parents’ place after this family get together and I went upstairs completely convinced I was walking into my girlfriend’s room. Her and her twin literally have identical rooms side by side, same dim lamp, same blankets, same layout. They’re one of those minimal ikea families.

So I walk in half asleep, get into bed behind her and immediately wrap my arm around her waist. She was wearing one of those oversized sleep shirts and I remember just instinctively pulling her closer into me and kissing her neck a little.

And she didn’t stop me.

She absolutely knew it was me from the second I touched her.
I only realized when she turned around and I properly saw her face. I remember whispering “holy shit” and trying to sit up but she just looked at me for a second, smiled slightly and pulled me back down.
After that it escalated really fast

A lot of kissing, grabbing at each other, both of us trying to stay quiet because everyone was asleep literally down the hall. I think the secrecy of it made it even crazier. I literally pulled her panties down and slid it first time cause of how wet she was. Every time either of us heard movement outside the room we’d freeze for a second and then go right back to it.

And honestly she was way more into it than I expected.

She’d only been single for a few months but I genuinely think she missed the attention and intimacy. There was this energy like she’d already thought about me before and the alcohol just killed the part of her that normally wouldn’t act on it.

The next morning was the funniest part honestly.

My girlfriend had absolutely no idea while her twin sister sat across from me at breakfast acting completely normal after what happened a few hours earlier. Every now and then we’d make eye contact for like half a second and both look away trying not to smirk.

We still haven’t talked about it.

Not once.

It’s been three weeks and now there’s just this weird tension every time we’re in the same room. Like we both know exactly what the other looks like in the dark and neither of us regrets it enough to bring it up. I still sometimes get hard thinking about how much she made me cum that night.