When I was young, I suffered from terrible ear and throat infections, which in those days were always treated with a big shot of penicillin. The visit to the doctor's office always began with having my pants pulled down for a rectal temperature check, and then -- since I was already in position and properly dressed for it -- a massive injection in the butt. The two experiences are inseparably linked in my mind. I think the rectal temperature was a way to quiet me down and distract me while the hypodermic syringe was being loaded and prepared, but the removal of the glass thermometer was almost always followed by the command to "relax and hold still" for the shot.
I know the doctor always checked my ears and throat -- but as I recall, he did that first, when I came into the office, and then the rectal temperature, and then the shot. If I wasn't sobbing from the sore throat and earache when I came in, I certainly was from the rectal temperature and the shot when I left!
Does anybody else remember a similar linkage in childhood experience?