Dear Dr. Myrtle,
I don’t know whether this is a problem, but I have noticed that when I self-pleasure or have sex, one or both of my testicles "disappear" up into my body. Is this a problem?
When people become sexually aroused, a number of different muscles involuntarily contract, which regulates everything from blood supply to positioning of genitals. One such muscle is called the cremaster muscle, which lifts the testicles up. While it is possible to voluntarily lift the testicles, this lifting also happens when the man is cold or extremely aroused.
The only time there would ever be a problem with the testicles rising up is if they don’t come back down again. Trapped testicles are painful, and the whole reason testicles are on the outside of the body in the first place (instead of being tucked inside like the ovaries) is so that they will stay a little cooler than body temperature (high temperatures fry sperm.) If a testicle should ever stay inside, take thee to a health care professional.