It’s an exclamation point on the most exciting play of the sport. You’re not directly taunting an opposing player all you’re doing is highlighting an exciting play you made. Just heard the Toyota Center get the loudest it has been all night while up 20 against the defending champs and a whistle takes the air out of the whole arena.
Pulling up is genuinely useful for killing your momentum though. Even people not showboating will do it naturally.