Definition of bottom on:
(v) :
(intransitive) To reach the bottom; to reach the nadir or lowest point.
(v) :
(idiomatic, automotive) Of a vehicle, to touch or drag along the ground or other surface.
(v) :
(idiomatic) Of a vessel, to touch the bottom of a water body.
(v) :
(mechanical engineering) Of a suspension or similar device, to strike the lower mechanical stop and lose the ability to buffer further downward motion.
(v) :
(intransitive, gay slang) To fully anally penetrate.