when you stick your fingers up ones asshole, then that person (the recipient of the fingers) licks the fingers, therefore licking their own asshole shit.

A pubic hair piece. A toupee for the pubic area/genitals. In the 1700’s when mercury was used to treat sexually transmitted diseases (Gonorrhea or Syphilis) one of the side effects was the loss of pubic hair. To disguise this condition, that was not cured by mercury, a Merkin was employed.