2 Chainz Sits in on Butt Lift Surgery, 'She Waking Up With a FAT Ass!'

Paging Dr. 2 Chainz ... Dr. 2 Chainz to the OR, stat!

Words we imagine no patient would want to hear, but that's what went down in Miami when 2 Chainz stepped into surgery for an up close view of a Brazilian butt lift.

The rapper streamed parts of the procedure Thursday on social media as the actual physician, Dr. Michael Salzhauer ... aka Dr. Miami ... went to work on a woman who dropped $10k for the procedure.

We're told the patient fully signed off on 2 Chainz sitting in, plus Dr. Miami was also streaming. Chainz, had full scrubs WITH all of his chains hanging outside though.