crease your pants
v. To have sex. The term comes from when pants are on the ground for a night, they tend to get creases in them.
Bridget: So, who's creasing your pants?
Ellie: None of your business.
Keith: So I creased my pants last night...
Mark: So I got my pants creased last night...
Beth: I've been creasing Keith's pants since January 08.
Lenny: Hey Jill, I'd like to crease your pants.
Ellie: None of your business.
Keith: So I creased my pants last night...
Mark: So I got my pants creased last night...
Beth: I've been creasing Keith's pants since January 08.
Lenny: Hey Jill, I'd like to crease your pants.