What is Butt Up?
1.
1.)When your underwear gets entrapped in the crack of your ass. Also see
2.)What a male might say after sexual foreplay just before intercourse when the female asks "How do you want it?"
d1.)Whenever I wear boxer briefs I always tend to get a butt up.
d2.)Female says: "How do you want it?" The male replies, "Butt up!"
See