Once a Democrat is selected to run against Trump, it is a sure bet that Trump will float out a derogatory name as a tag for his opponent.
It is important for the Democratic Nominee to have a fast come-back that will nail Trump at his own game.
That being said, I offer this as a possibility:
President Trump, you surely look slim up here at the podium. Are you wearing a spanks, or a full figure girdle? You know, I’ve seen you out on the golf course where you look like a fat walrus with teeny tiny hands. I think I will call you tt for teeny-tiny, or else tw for teeny-weeny………hands.
Democrats are always quick to say, if you wrestle a hog in the slop, you’ll get filthy and the hog will enjoy it. Also, when they go low, we go high: but that’s not going to work with Trump. Sometimes you have to wade into the slop to kick the hog in the ass.