MO is a word used to describe the feeling you get when a
person is just chilling, typically on a couch, in a car seat, or in class and you get a sudden urge to subtley jerk into movement. Some poeple call this "getting the chills". However, the deal with MOs is that if you get 8 in one 24 hour span, you have officially had an
orgasm.
Bryan Matt coined this phrase.