The move is performed by catching an opponent off-guard, usually with a kick to the gut, then proceeding to hold his head with both hands while turning your back on him, and slamming his jaw against your shoulder. But that's the basic variation. Plenty of wrestlers can do this fairly decent move which, if executed IRL it can deal some good damage.
The real reason this variation is the big travesty it is, involves the reaction the victims are suppossed to have after being stunned. Yes, because we're expected to believe that the sheer force of the stunner causes the victim to bounce off the ring canvas and reach a point of complete upside-down verticality, after which the body can finally land face down. Come on. Even for circus wrestling standards, that's beyond ridiculous.
Jerry Lawler: Funny, I didn't bounce off like that last time he stunned me.
Lawler:He dropped the stonecold stunner!!!
JR: Oh my gawwdd!!!