My NM is obsessed with body functions too. She is obsessed with body parts of animals, etc. I bought a set of these really nice German-made animals for my daughter, a cow, horse, pig, rooster, giraffe, dog, duck, tiger, and a lot more.
Well, the animals are plastic but really well made and collective pieces. The animals are painted and have near anatomically correct bodies; NM turned each one over and pointed at the penis' of each animal and laughed hysterically. She kept picking up each animal one by one and pointing to their private parts and saying, "heee heeee, look at this one! Look at this, ahhhh haaaaaa" and putting her finger on the giraff's and horse's penis, etc. She was like a child!!! It was so bizarre! Mind you, the private parts of the plasitc animals were not THAT obvious to me or anyone else in the room but she made them obvious and thought it was so funny. I hadn't really noticed them even until she made a big scene about them.
I was so embarrassed!!!!!