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."