The OTT (or colloquially "the O-double-T") stands for
Over The Top.
Taking the name from Sly Stallone's 1987 celluloid tour de force about a man earning his estranged son's love through arm wrestling, it is an advanced form of the
Eiffel Tower Play. Instead of slapping high fives over the
double stuffed ho the two gentlemen engage in an arm wrestling contest.