Justin Bieber Uses Post Malone ... As An Ashtray

4/11/2016 11:24 AM PDT

Justin Bieber Uses Post Malone As An Ashtray

EXCLUSIVE

Justin Bieber gave Post Malone a sick burn ... literally.

The Biebs was onstage at a Houston club, where Post Malone performed the hit song "White Iverson." Bieber appears to be smoking a cigarette -- or some other rolled up joint -- and apparently couldn't be bothered to look for an ashtray. 

Enter Malone's arm.

To his credit, Malone wasn't fazed and continued like a pro ... but check out Bieber's reaction at the end of the video.