Getting absolutely, totally, completely annihilated during homecoming festivities. A whole helluva lot of alcohol and/or drugs are most certainly involved. This can (and very often) result in one or more of the following:
Memory Loss
Dizziness/Loss of balance
Waking up in a random location
Random cuts, bruises
Ending up getting intimate with a complete stranger (or two)
Vomiting
Making a fool of yourself and ending up on Youtube/Facebook/etc for all of eternity
One might say "oh so you just got fucked up then?" No. Getting "homecominged" is "fucked up" multiplied by about a billion.
"I woke up in the middle of Aberdeen wearing nothing but fuzzy slippers and an inner tube. Apparently I've got lipstick on, and I'm a guy. My ass got homecominged."