Trashfest
Deriving from the term Trashbag, the Australian term trashfest, is the event at which a trashbag displays all aspects of party-animal like behaviour that allows them to proudly call themselves a 'Trashbag'. i.e at a party or the races.
"We had the biggest trashfest last night, I fell asleep on the roof and somehow aquired a pet spider monkey."
Trashfesting
Attending a social event that is not necessarily a party, but wherever you are present there is a mini shit show happening.
Man, I definitely had 10 too many drinks at my high school reunion. I was trashfesting while everyone else was speaking of their great jobs and kids.