It is when your woman is doggy style or bent over the bed, ass in the air. You lube or Vaseline her hips and crotch, entirely. Then do the same to yourself with your choice of delight enhancing solution for your Greasy Gumble.
Then, position yourself across the room, as far away as possible while still being lined up with your partner. After achieving a full errection, use viagra if you wish but is not suggested. Then without warning, take full stride towards her all while screaming "GREASY GUMBLE GAMBLE!" As many times as possible.
The full point is in the gamble on which hole you end up inside. Or, possibly none even at all. Risk of serious injury is possible.
'thebestman' asked his woman to 'Greasy Gumble Gamble' with him. "It could be fun!", he added.
The 'Greasy Gumble Gamble' can be chill to try. Just don't attempt to Superman on your way in. "Your gonna have a bad time!"