buttheading 

a bit like headbutting but instead it is the act of randomly running behind an angry mob and using your head to ram their asses.

lets go buttheading into that angry mob of bearded bald men

buttheading by mike blown January 17, 2008

Buttfeeding

It's where one person puts a banana in their butt, and then someone else takes it out. by way of eating the banana. Similar to Cool Butt feeding, but not specific to one person.

"So this one night, Sally buttfed out of Johnny. I didn't know what Buttfeeding was so she called me a douche bag."

Buttfeeding by LOLflute November 8, 2009