I suppose when I was a baby, my mother must have taken my temperature rectally, but of course, I have no recollection of that.
She would be the only person who has taken my temperature rectally.
My wife, if I asked her, would be happy to add to my list of kinks by taking my temperature rectally, not because it would turn her on in the least, because it wouldn't, but because it would float my boat, and she is happy to float my boat, that is, pleasure me, because she loves me. She already happily accommodates my 69 other kinks, plus or minus 33 kinks, so what's one more kink, especially an easy kink like shoving a small rod up my caboose, especially when many of the other "kinky" objects take considerably more effort to breach my bum hole and/or make their way up to my tonsils.
By the way, this is not a one-sided situation. I am also happy pleasuring my wife because I love her, too, but accomplishing that, that is, pleasuring her, is relatively easy because her sexual needs are relatively few and I have had nearly 50 years to learn them (both of them) and they have not changed in nearly 50 years, and, additionally, she has no kinks, that is, she is pretty vanilla...very vanilla.