When I was in highschool, I went to a New Years house party with a couple of girlfriends. The party is at the house of a friend-of-a-friend, who is a couple of years older than us and lives on his own. My friend "Cathy" and I don't know the people there very well, but we quickly make friends and have a blast. We befriend the guy who's house we are at, who is a goofy, funny, slightly awkward dude. We like him! He quickly becomes one of our drinking buddies and the night goes on.
Anyways, a bunch of people decide to crash at his house, including me and Cathy. The couches and floors are covered with beer and drunk passed-out people, so he offers up the top bunk in his bedroom. Cathy and I clamber up and continue to goof off, drunky-pants style. He climbs onto the bottom bunk and is talking to us from below. Anyways, the hours pass and Cathy and I are still nowhere close to sleeping. Guy continues to talk to us every few minutes, so we know he's awake. Out of nowhere, I hear a weird sound. Naive as I am, the first thought that comes to mind is of somebody rubbing a gym bag with their palm. "Guy?" Silence. Rub, rub, rub. Cathy looks at me. "Guy?" Silence. As the speed of rubbing intensifies, it dawns on us what is happening. Cathy's eyes are wide as headlights. Fapfapfapfapfapfapfapfapfapfap. We have no idea what to do. We lie, horrified, in silence as the terrible sound of fapping surrounds us. All of a sudden, we hear - fabfabfab "HHHHHNNNNNNNGGGGG!"
Holy shit. Cathy and I lie in silence for another minute, and as if reading each other's minds we bold out of bed, out of the room, and into the livingroom where we dash to the table to grab our shit to GTF out of there, half laughing, half crying. Then we hear, barely a whisper - "ahem." We spin around, and Guy is standing in the corner, with his hood up, his face in the shadow, flipping a switchblade between his fingers. "Where are ya guys going? ... It's 5am"
Our hearts drop. He offers us a ride, but we make a meek excuse, thank him for the party and bolt... he stares at us from under his hood the entire time. A week later he's super pissed that we told our mutual friend about what had happened, and starts spreading rumours that we were touching his special place and coming on to him in the bedroom, that we were lying and that the fapfapfapping never happened.
TL;DR Some guy we met blew a load all over himself while my friend and I were clearly not sleeping on the top bunk, then followed us out of the room when we bolted and was super creepy about it.