Usually seen in Mixed Martial Arts competition. Where a fighter taps once to get out of a submission (so the ref stops the hold) and then carries on fighting on hoping to continue the fight and win.
It is a subtle form of cheating and is frowned upon within the sport.
At UFC 117 Anderson Silva caught Chael Sonnen in an triangle choke submission.
Chael executed the "Brazilian tap" so the ref stopped the fight.
Chael tried to keep fighting but the ref was having none of it and Silva won the fight.