Assfoot is what happens when Dad finds you masturbating while peeping through a hole in the downstairs shower, to your mom, sister, cousins, etc., anyone with ass, cunt, and tits.
Derived from the Soul Caliber character "Astaroth" an asstooth is a big, bumbling, klutzy galoomph of a person who is obviouslydoing something that requires negative use of the brain.