To pass out due to drinking before midnight, generally causing this person to miss out on something cool or extremely fun happening later in the night.
Drew, if you didn't ass out you would've seen the stripper urinate all over Chad
verb: To "ass out" is akin to "passing out," although it generally means going to sleep in a haphazard manner as opposed to becoming unconscious. For instance, after a long night of partying, one will generally ass out as soon as they get home, often falling asleep with their clothes still on or maybe on a couch.