When someone walks in front of you getting to their seats at a sports event and they choose to go facing you. If you are still sitting down then it will be their crotch to your face. This is considered poor practice and should be replaced by their backside in your face.

when your dog hears something and its ears go up and get all stiff

An Alzheimer's Purchase is when you buy something online that takes so long to be delivered, you forgot you ordered it in the first place.

Walking directly behind someone who is pushing through a crowd, to avoid having to push through the crowd yourself. Only works if you stay in the empty area directly behind the person in front of you. Usually done behind someone tall or buff.

Cyber-sex. Online roleplaying mimicking sexual intercourse.

A group of people surround a lone person on the dancefloor and when appropriate begin twerking aggressively on the person in the middle. The tighter the circle during the twerk the better. It is typically performed during r & b or rap music.

Long winded, boring, nauseating, uninteresting description of an event or the story of someone's life.