1. Slang term for the hair style commonly reffered to as a "mullet," "Kentucky Cascade," or "Camero cut." The term is derived from the ratio of hair in the back (90%) compared to the front (10%).
2. A favorable smell ratio between vagina and asshole experienced during a 69.
1. The male of the species will often fluff his 90-10 before entering a Denny's. The goal is to attract a suitable mate.
2. She was a very nice girl but she wasn't quite a 90-10. More like a 60-40.