Sphincter!
Now that I’ve got your attention, I’m going to drop some science on you. There are some crazy scientific words out there that sound dirty but aren’t really, and are really funny to say regardless.
Like sphincter. Through association with that most famous of anatomical regions, the hindquarters, the word has developed something of a reputation but sphincters play a much larger role in the body than merely retention of...shall we say bodily waste for deposit at a more appropriate locale.
According to wikipedia my own encyclopedic knowledge, there are over 60 types of sphincters in the human body, and millions of individual sphincters, most significantly, precapillary sphincters that help control blood flow. There’s even one in your eye, the pupillary sphincter, that helps to retract the pupil in response to bright light.
It’s a handy insult in a pinch, but when you really think about it it shouldn’t be. Sphincters are very important muscles. We couldn’t live without them.
So the next time someone calls you a “sphincter”, you say to them “Thank you for the compliment, good sir!” and respond in kind, because it pays to be polite.