As I have allready indicated in several posts, the only time my teemperature was taken as part of a medical examinaation was my school medical exam in my last year of high school, back in 1969. After the genital exam, the school doctor, a nice looking lady by the way, sitting in front of me standing up, asked me to "turn around" and then, without any notice, she parted my butt cheeks and inserted a thermometer. I felt humiliated, with a thermometer in my ass like a baby, especially as two other persons were present, the nurse and the school psychologist. I was about to cry. At least, the girls in my class did have their temperature taken lying on their stomach.
Having told this episode to my present girlfriend, she now likes to take my rectal temperature, me standing and her sitting on the bed or a chair, as part of our sex games. She has even developped the scenario in taking care of my penis or my testicles as we wait for the thermometer to register.
And I agree with et986, without any sexual implication, fairly often, if I don't feel well and want to know if I have a temperature, I put the thermometer in my butt and it records my temp as I shave