The Reversy Percy is a heterosexual move whereby the male partner goes down on the female partner of whom is wearing a strap on penis / dildo, while the female partner licks his anus. Thus a Reversy Percy is simply the inverting of a couple performing the 69 sexual position.

A truly sickening sexual deviation. It involves the male partner tucking his erect member between his thighs and trapping it there, poking out backwards like a straightened out pig's tail.

Reversy Percy (Ree-vursee Pur-see)
a. After narcotising someone with Rohypnol AND Viagra, then climbing on and having your wicked way with them/yourself, entirely without your victim/abusers knowledge, you can claim to have performed a Reversy Percy, a feat of such moral paradox and logistical difficulty that it is topped only by a Hitler Youth DVDA.

b. Bag of sweets sold by popular British high street retailer, Marks and Spencers.