Why I Don't Teach my Kid Correct Terminology for Body Parts

The old classic debate of whether or not to refer to private parts by their anatomical name or some made-up name has never been an issue for me. I will never think it is normal for a 5 year old to say the word "vulva." So, once our kids became vaguely aware of their bodies, we decided on our nicknames for these parts. A penis was a "weiner" and a vagina was called a "girl part" (I never said creativity was my strong suit). So all was going according to plan until someone, somewhere decided to teach my 6 year old twins the word "anus." It is bad enough when I hear an adult say it (like when I am at work and I ask how a child's temperature was obtained and they say "anally"), but to hear a kid say it is just wrong. I'm assuming they picked up on my disgust because they took this opportunity to take that word public. They loved nothing more than to trip and fall in target and announce loudly for all to hear, "Ouch! I fell on my anus!"
But I can't take all the credit for my disdain of appropriate terminology. When I had baby number 4 and that preciously awkward conversation took place as to how said baby received its milk, my kids decided that they didn't like the term breastmilk.  So, when the baby cried, they took no issue with announcing for all to hear about how the baby needed his "nipple water" and how he only likes me for my special nipple water. And why refer to it as water instead of milk you ask? Well because one day, when I was in a 2 hours of sleep per night coma, they found a bottle of milk I had just pumped and dared each other to taste it. Somehow, my kids that literally won't eat a single vegetable, gulped it down and declared that it just tasted like water! I guess they weren't too scarred from the incident because a few days later when we ran out of milk, my daughter asked me for some of my nipple water for her cereal!