A Twiggy-Back-Ride is when someone gives a
drunk individual a piggy-back ride to their
car or
house to ensure they get there safely, and the drunk person involuntarily urinates on the back of the ride-giver.
"
Man, I tried to do a nice thing and
carry this wasted girl
back to her apartment, but as soon as I felt this warm moisture on my back... I realized my good deed had turned into a Twiggy-Back-Ride."