There was a video I think here a while back showing some guy doing a Gi choke in competetion on people and they were all passing out before they could tap. Seems like it was with an over and under grip off your back and when they pass to side you basically rolled with them. Anybody remember it, I can't find it anywhere.
He calls it the "gator choke" here ya go... Im pretty sure this is the one you are talking about... YouTube - Gator Choke tutorial
Baseball bat choke from guard. Grab your grips like you would a baseball bat. Make sure he passes to the side your thumbs are pointing. Kinda a gimmick choke, in my opinion. Works once or twice on the same person before they become wise to what you're doing.
In the video he lets the guy pass the opposite way the thumbs are pointing... Im pretty sure that is right (well, bc the guy ended up unconscious and...) because the hand that is palm up can use that elbow to drive the persons head down, otherwise the person will be able to pass without the choke being applied. However, it might work the other way but I can't picture it...
As long as you spin under him, I don't think it matters. Not certain though. I hate that shit anyway. EDIT: Spin the direction that your thumbs are not pointing. I've choked someone out letting them pass the direction my thumbs were pointing when I first saw this move, so I'm not sure.