topshark
It is one of the forms of the art known as "Japanese Sharking". "Topshark" refers specifically to form of it where someone(the shark) pulls down an unsuspecting girls top, exposing her breasts, while an accomplice videotapes the event.
I saw that video on the internet the other day where that girls was totally "topsharked" and her boobs where completely exposed to the public!
topsharking
Pulling down an unsuspecting girl's top and/or bra, exposing her breasts. Best done in a public place for maximum shame factor
I went topsharking at school today, and the freshman chick squeaked while all the senior guys watched her big bare boobies bounce.