An event that causes the crotch area of your pants to split. Also, a story so funny it has the potential of making you laugh so hard that the crotch area of your pants might split.
Megan: So, my boyfriend, Will, who lives in the Palisades, split the crotch of his pants while test-riding his new bicycle. He's exposed. I'm sorry it's so funny, but I can't help it. Will doesn't understand why his crotchsplitter of a story is so funny.
Mike and Susan laugh uncontrollably, almost splitting their crotches.
A person can be a bag of crotches when calling them a crotch or crotchity is just not enough. This is a person who not only steals your job, but insists to everyone in your workplace that he or she is waaaaaay better at it than you are, and that he or she is always right, and can NEVER be wrong.
Amy is a Bag of Crotches. If I say something is blue, she will tell everyonethat it is red, and somehow they will believe her.