My co-workers and I are in a dispute over anal sex and the sphincter muscle. One woman said that the muscle will lose its ability to close if you have a lot of anal sex. I and another person argued that this muscle will always close back to its original size no matter how many times you have anal sex. Would you please settle this issue for us? Thanks.
Congrats, I think you just won your bet!
The anal sphincter muscle is designed to expand and contract an unlimited number of times. Stretching it will not make it any less able to constrict, just as stretching your hamstrings does not make them weaker. There have even been a number of long-term studies that found that there was absolutely no loss of muscle tone or the ability to contract regardless of the amount of anal sex a person has had.
Of course, it is always important to remember that anal sex is an easy way to give and receive sexually transmitted infections so be sure to use condoms consistently during this activity. However, becoming unable to close your anus is not something you need to worry about.