What's a "Swim move"?

[rainmaker]

Mark T D'N:

Thank you for this excellent explanation. It hits exactly on my confusion, and makes the situation much more clear. I think you are saying that the best thing for the Offensive player to do, is to step forward into the contact so that the defender has committed a foul and can't gain the ball. This is how I have called this contact in the past, but I didn't realize that the "swimming" was the first illegal move.

Extrapolating a little, if a dribbler is driving down the lane, and a defender puts an arm out horizontally, we call a block if the dribbler runs through the arm, but if the dribbler puts up his off hand and pushes the defender's arm out of the way, is it now PC?