when you're riding in a car with a drink in your hand and you have nowhere to set it down, so you put it in your crotch so you don't have to hang on to it anymore.
"I had nowhere to put my drink so i had to crotch it so i could smoke a cigarette."
A club formed by the first person to get caught itching their crotch. To become a member of the this elite club you must get caught itching your crotch by someone already in the club.
I became a member of the ItchCrotchClub in the hall at school.