We do not know much about this clip other than what's in the YouTube description (and that it's pretty funny.)
A rugby match between Vaiala and Vailele, stirs some funny moments between the players
Two players from these Samoan teams exchange a few slaps after which one of them takes a dive, possibly in jest, though he may just be trying to laugh it off as a joke after realising the ridiculousness of what he has done.
Either way, the crowd thought it was hilarious.
h/t Rugby Onslaught