Tristan Thompson Trolled By J.R. Smith: You Buyin' Fur Coats For Your Baby??

Tristan Thompson got totally roasted by his teammates during a fan event Sunday night ... when he was asked if he's already gone fur coat shopping for his baby with Khloe Kardashian.

TMZ broke the story ... the Cavs star and Khloe -- his girlfriend of 1 year -- are expecting their first child together.

So when T.T. was asked about having "his and her" fur coats with Khloe at the Cavs' annual "Wine & Gold United" event on Sunday, J.R. Smith decided to tease Thompson about his new addition.

"You gettin' infant fur, too??"

You gotta see Tristan's reaction ... and his teammates absolutely lose it.