When someone encircles your butthole
with their finger (preferrably pinky) while orally stimulating you, gradually easing the finger inside of you until they are knuckle deep in your pooper
. Surprisingly sensual and recommended for uninhibited and particularly dirt nasty couples. Named after the equally surprisingly erotic musical artist Regina Spektor.
Me: Dude, Wayne gave me a Regina Sphinkter last night unexpectedly and who knew I was such a filthy, filthy whore!
Them: Um, everyone?
Me: That's beside the point! Reg Sphinks rule!!!!