The definition of the word creasage is when you find something really funny that makes you laugh your head off. Also another word for creasage is lolage or lol.
The "proper" term for Butt Cleavage, made accessible to booty watchers everywhere by ultra low rise jeans and pants. While sometimes seen with a whale tale, au naturale is the preferred display. This is the also discreet way to refer to it when seen in the wild.
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi