Dog gets really mad when temperature is taken

We just adopted a 3 year old chocolate Lab last week. He’s an absolute sweet heart in every way, and we do plan on putting him through obedience training. He’s great with getting his teeth brushed, being brushed, getting his ears cleaned. But we found out when we took him to our vet to be microchipped and for a full physical that he gets pretty darn mad about having his temperature taken. Any suggestions on now to train him to be civil for as the vet called it “butt things.”