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."