What always amazed me was how my mom could insert the thermometer into me without separating my bottom. I would be lying down on my tummy with my pants and the underwear pulled down, head turned to the left waiting while she prepared the thermometer. I could feel the bed go up and down as she snapped down the thermometer while sitting next to me. After that I would hear the lid of the large round jar of Vaseline being opened. At that point I was totally focused on my bottom. Then she would slip the lubed up thermometer deftly into my rectum , never having had to separate my bottom. Some how she always found the target. The few times my father took my rectal temp, he would use the thumb and forefinger technique to visualize the target, but not my mom. How about your experiences?