Alternate angle shows that, after the buzzer sounded, Devin Booker walked over to the Clippers bench to taunt/gloat. The shove by Cousins followed shortly after:

Healthy Clippers vs Suns -- 2021 Playoffs

Tyson Chandler flops to give Cousins his 6th foul.

Booker hits the tough shot to end the 3rd quarter

Curry can't get the game-winning 3 to fall at the buzzer - game headed to OT