B.J. Penn, Lyoto Machida and Sam Greco

that's antonio inoki, a famous pro wrestler in japan. you may remember him as the pro wrestler who had a match with Ali, where Inoki worked from his back the whole fight....inoki is huge in japan, he was a member of their parliment..... he is also a major benefactor for Machida in his early career. He fought on some of Inoki's bomb-bah-yay card's and Inoki was instrumental in gettin him an in with the K-1 folks. The slap is part of inoki's gimmick (not sure what it signifies) and he basically did it on all the shows he was involved with, pride, k-1, etc..... i think i remember seeing him on a bushido card and he was bitch slapping some lightweights and they were just loving it, and considered it an honor.