It's...a guy!

"God, I love watching you come, Steve," Suzi said, looking round the door.

I moaned as my cock pumped come through the wall into the tight ass I'd thought was Suzi's. "Who? Wha..?" I babbled.

I tried to pull back, but my cock head was swollen up so I couldn't withdraw without yanking it out and maybe hurting whoever it was. As much as I felt tricked, I didn't need to be a dick about it. I closed my eyes and held on as my last spurts filled the end of the condom. I shivered a bit as a cold draft chilled my bare butt. After a minute, my erection subsided enough that I could slip out.

I quickly looked through the knothole and saw the butt I'd just been fucking. There was a smooth cleft between pink cheeks, a tight, lube-slicked hole...and a pair of dangling balls! I blew my load inside a GUY when I thought it was Suzi!

I looked over at her. "Su--zi!" I said. "What the fuck?"

She laughed. "Take it easy, Steve," she said. "It's not like he's a stranger!" She winked at me and half-whispered, "Not like it's your first time either." My heart skipped a beat. She knew about that one time in college that I...?

"Come on round," she said, waving me toward the door, "You must be cold standing there in with your pants down!"

I grabbed a wad of tissues out of my pocket and disposed of the spent condom, then I yanked up my pants and walked hastily toward her. I was going to get to the bottom of this trick right away.

As I approached, Suzi backed through the door. I stepped round to see...