When a girl is taking a huge dump on your chest and right after it falls onto the guy's (or girl's) neck, they begin to gentlely lick the anus of the aforementioned shitter.
Tom: Alright baby, SHIT ALL OVER ME!
Jenny: *pushing hard* Fuuuuuccckkkkkk!!!
Tom: Are you ready for a Shit n tickle? *licks jenny's asshole*