Although it seems like a hollow threat, can be extremely effective. Often, however, leads to unhealthy relationships as the threat begins being used more and more often and for mundane things. Generally used when a girl thinks she has a lot of hand in a relationship.
Guy: Hey babe, lets go to second base...
Girl: Stop taking my chastity bra off!
Guy: Come on babe, I want to make you queel.
Girl: I'm gonna yell!
Date 6 (mediocre use):
Girl: I want the last avocado bruschetta.
Guy: Let's split it.
Girl: I'm gonna yell.
Guy: Fine, have it.
Date 12 (inappropriate use):
Guy: I got you this flower babe.
Girl: WTF is this ugly ass daisy. I'm gonna yell.
Guy: No please don't! What do you want!? Anything!
Most people say that Yell folk shag sheep. No one is sure if this is a one night stand or a serious relationship.