Anytime that you think you will be getting to have sex, or the feeling that you need to engage in a sexual act. I guess booty or booty time probably originated from, "brothers" referring to getting with a girl because the large buttock seems to be desired of them. Booty time is a two part word.
If you are excited about going to the bar and finding that special one night someone, you might tell your friends, "It's bootytime". Or if you get hit on by a special someone you might say to your self or anyone near by when the person who engaged you is not listening, "Its booty time".
by voodooredfrog April 04, 2008