DRAKE GOT HI DURING PERFORMANCE WITH WIZ

If you're Drake ... and you're going to smoke your first on-stage joint ... who better to inaugurate you than Wiz Khalifa. 

Drake was performing in Houston over the weekend when he was joined on stage by Wiz ... who is never weed-shy.

Drake -- who confessed he's never lit up during a performance --  said "f*** it", grabbed the joint and puffed away.

They say you never forget your first time, but in this case ...