This fetish is the act of eating or getting your partner to eat a lot of corn, waiting until they defecate and pick the loose corn out of the shit and have the other person eat it.
Me and my girl tried corning, we loved it and now we do it every week.
The act of fully inserting one's cranium into a women's vagina and ideally crawling into her womb. It is the reverse of the birthing process, specifically crowning. It is advisable to cover one's head in a balloon of some sort in order to maximize pleasure.
Guy: Dude, I want to finger that chick.
Experienced Friend: No man, you gotta try reverse crowning.