I got rectal temps quite a bit in childhood and teens... and even now, as a young adult, by my mum and dad sometimes, and by my older brother whose extremely strict about my health as I am quite lax about it. Sometimes, I also get it as punishment which is always, always followed by suppositories, just to keep me in check. My sister-in-law too quickly learned the ways of our house-hold and sometimes if she and me have any sort of disagreement or sometimes, plainly to scare me, she threatens to tell my brother or parents about some made-up misdeed of mine. Thanks to some of my bad behaviour in the past, they always believe her and I end up with the thermometer in my anus, whether I like it or not. The whole thing leaves a very smug expression on my sister-in-law's face which I hate. She knows she has control over me, in this respect. I also hate it and feel highly embarrassed when she helps with my rectal temps and suppositories and watches over my bare bum.
Once, during my teens after a minor argument, she blew up the whole thing disproportionately and told my brother the entire thing with a lot of stuff added from her end which never occurred. My brother pulled me into the bedroom by my ear, me crying and repeating I hadn't done half the things my sister-in-law said. This angered him even more as he said I'm branding her as a liar.
Once inside the bedroom, he pushed me on the bed, on my back. I realized, much to my horror, that it's gonna be in the diaper position. She lifted my legs by my ankles and bared my bottom by slipping over my pants and panties. She did it very slowly only to increase my embarrassment and shame. She smacked me hard on my bum and asked me to be quiet as I was gonna be punished whether I liked it or not, no matter how much I protested.
I saw the thick glass rectal thermometer glisten in my brother's hands. He separated my butt cheeks and with one finger, liberally applied a lot of Vaseline both on, around and inside my anus, going in and out a few times, clockwise and counter-clockwise, everything being watched by her. Then he kept holding my butt cheeks separated, and also took my legs in the air, from her and asked her to take my temp. I protested saying I'd rather he did it. All I got in reply was another hard smack which made me squeal.
She took the thermometer, lubed it a bit and started inserting it slowly in my rectum. Gosh, I was so embarrassed being punished by her, for something I hadn't even done. She took it out a few times, twirled it too, pretending it was for adjustment but I knew it was intentional. After inserting it sufficiently, she kept her hand on my bum to hold the thermometer in place. The minutes ticked away and the scolding and lectures continued from both of them. After what seemed an eternity, they both looked at each other and nodded. She pulled it out slowly and checked the temp. Then my brother took over, she went back to holding my legs still in the air. Generally, he inserts two suppositories and then a butt plug but this time he inserted something which made my anus sting and burn like crazy. Seeing me squirming, a slight laugh escaped her lips. He said, he had given me a ginger suppository for added punishment. She pinched my cheeks together for a while to ensure I felt the burn even more. I truly felt punished and humiliated.
I try to be careful around the house but can never be too careful.