A girl who rarely moves while doing the nasty. While having sex, one could confuse said party of being a dead possum. This does not include muscle spasms, or other contractions of the like.
Danny: How'd it go with that girl last night, Dave?
Trying to wake up a whiskey dick. So named for the dead, unresponsiveness of a whiskey dick (playing possum) and the vigorous assault one makes on said dick in an attempt to wake it up.
Went home from the bar with some skank and was possumflogging for half an hour trying to get it up!