I'm so slick that they need to call me grease
Cuz I slips and I slides when I rides on the beast
People often put grease on things to make it “slick” or easier to move (i.e a door hinge). People often slick their hair back with grease. This is also his way of saying that he can get woman. grease
Rides on the beast refer to sex with a woman, while slips and slides refer to his movements while having sex with that woman.
To help improve the meaning of these lyrics, visit "Oh Shit" by The Pharcyde (Ft. Paul Stewart) Lyrics and leave a comment on the lyrics box