Sphincter Plinko

(sfink-ter plinck-o)

The act of having a group of people bent over naked around you in a circle, and then using your erection to penetrate different anus' quickly and briefly at random.

"Oh man, my Friday night was awesome! We had a couple people over, had a few drinks, and played Sphincter Plinko. Talk about putting some stank on it, Yeah Boi!!"