Wiz Khalifa -- I'm Busting Out of This Joint ... With a Hot Lady Train

Wiz Khalifa was the pied piper of groupies Wednesday night in Los Angeles ... but instead of a magic pipe, the rapper was happily wielding a joint.

Khalifa was heading out of Warwick in a very Bieber-esque outfit -- all denim and an unbuttoned shirt -- but that didn't stop a whole train of women from piling into his SUV. Dude's been on a streak.

The only bad news for Wiz ... he dropped his joint outside the club, and you can hear in the clip -- he wasn't happy about it. But really, the chicks are the reason to watch this vid.

Best parade ever!