The action of tickling someone so vigorously and relentlessly that they shit themselves from laughter. It is used to humble and humiliatepeople who hate being tickled.
"If you don't stop singing that stupid song, I'm going to shit-tickle you."
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!!!
Turd: *plop*
Tom: Are you ready for a Shit n tickle? *licks jenny's asshole*