Nick Young On Iggy Azalea's Ass -- 'What I'm Gonna Do with This Shouldn't Be Legal'

Who needs playoffs when there's QUALITY ASS to tap? Not Swaggy P ... 'cause after the Lakers final game last night, dude was FIRED UP about takin' it to the hole with his rap superstar GF Iggy Azalea.

Nick Young and Iggy were leaving 1 Oak on Sunset Boulevard when we asked how he felt about critics who believe Pau Gasol should have addressed the Staples Center crowd at the last home game ... instead of Nick.

What ensued was INCREDIBLE -- "I'm the star! I'm Swaggy P! You see what I'm going in this car with? (points to Iggy) ... What I'm gonna do with this shouldn't be legal ... ALL OF THAT ASS!!"

Swaggy was the only part of the Lakers worth watching at the end of the season -- crushing it even when the team was losing -- so, if dude wants to celebrate ... CELEBRATE!!!

You earned it.