A Noun or an Adjective describing or defining a Slight variation of the motorboat
. However the motorboater is typically a male, and instead of the normal medium for motoring, breasts, it is performed to another males ass hole. Another variation from the original move is the heavy usage of tongue in this foreplay maneuver. So a Davis is a man who likes to put his face inside another mans ass and lick and blow on his asshole. Or a man can perform a Davis on his friend.
After they had talked for a while steve found out brad liked to davis, so he dropped his pants and bent over.