It comes from the saying "awesome possum" according to the special ones meaning me :P if you are possum you are awesome. if I know you, you are possum, although there are rankings of possumness....ness . Opposite affect is if i don't like you you have negative possum odor. All true possums know the "nega-possums." Enough said.
Someone who is unattractive that believes they are attractive. She is playing possum, just like possum play dead when they aren't, she played attractive when she wasn't
Oldfemales who are completely unattractive but think they are. She was playing possum with us.