One Direction We Won an Award ... That's NUTS!!!

5/17/2015 7:30 PM PDT

One Direction -- We Won a Billboard Music Award ... That's NUTS!!!

Harry Styles paid tribute to 1D, as in ... DEEZ NUTS ... in Las Vegas.

One Direction won the Billboard Music Award for Top Duo/Group, and Harry celebrated by slyly grabbing a hold -- playfully and gently, we hope -- of bandmate Niall Horan's balls.

Watch ... Niall plays it off pretty good.

Not sure Harry even asked him to cough first. So rude.