New to polo, start here: a guide for beginners

throw-ins: is any informal game, just x numbner of mallets to the middle, shuffle and play
BM: bench minor is a new format of game, take it from ice hockey, you have 8 or 10 players per team, that rotate to play a normal 3x3
T-boning: *side impact collision, making the shape of a T
*

Nb, the descision of which part of the t is at fault is more or less moot when starting out... So it's just as bad form to stop infront of someone (creating the top on the T) as it is to ram someone.