Sayings...

[X]

My favourites for describing a real ugly girl you pulled.

Double Bagger, a girl so ugly you need to stick two bags over her head just in case one comes off.

and for the real moose.

Triple Bagger, two bags to cover her head, the third one is for yourself just in case they both come off :P

Coyote Triple Bagger - the three bags are used as you describe, Bilbo, but you also have a coyote on standby in the bedroom, so it can gnaw your arm off in the moring so you don't wake her up when you leave.

How about Coyote Replacement a girl so ugly that the bags don't work so you bang the coyote instead :P