When a man stretches his sack out far enough so that it looks like a pair of bat wings

Over-The-Pants-Hand-Job. Distant cousin of the dry hump.

A sexual maneuver in which the man holds the woman upside down, like a bat, with her back to him and her head near his feet, and she holds onto her own legs to raise up and support herself perpendicular to the man, so that intercourse can take place. Requires a short woman, and physical strength on the part of both the Batman and the Batgirl.