Drake & Rihanna Hit the Strip Club -- Drop $17,000 on Houston Booty -

Drake and Rihanna are investing big in the Houston stripper market -- dropping a combined $17,000 Thursday at a H-town gentlemen's club ... and we found some booty-bouncing video.

Sources at V Live Gentlemen's Club tell us, Rihanna arrived around 2AM and Drake showed up about 30 minutes later following his show at the Toyota Center.

We're told Drake threw down roughly $12,000 and Rihanna dumped an additional $5,000.

You can't see Drake and Rihanna together in the video, but we're told they sat side by side in the club -- and eventually left together after 5AM. One source said the two were touchy-feely and looked like a couple.

Throw it up, throw it up.