The next stall is occupied

You hadn't thought about it before, but you are wearing very quiet shoes. The bathroom didn't have a door, just a hallway with a turn that obstructed the line of sight. You assume you're alone, but when you reach the first stall, you hear a noise coming from the larger, handicapped one.

Quietly creeping out of your stall, you peek through the crack between the door and the stall. You are greeted with an astonishing sight:

Lucas, a popular jock, is sitting on the toilet seat, holding some kid you don't know. Both are stark naked, and it is extremely obvious that Lucas has his dick up the skinny kid's ass. The kid also has a massive boner, almost impossibly big for his small size. Both are moaning like dogs in heat, although Lucas's is more of a growl than a moan.

You jolt back in surprise, so quickly you fall on your ass, hitting your head on the sink behind you.

The moans suddenly go silent.