Mommy Moo's, can you?

So, Bo & I shower together basically every day. That has been the case for quite sometime now. When we first weened her from breastfeeding, I had to wear a swim suit top in the shower each day. But we have been passed that now for about 2 months or so.
Anywho....she has just recently become interested in my boobs. Do not know where it came from, it started just last week. The first day she showed interest, she thought it was funny to smack them around a bit. She would swat one, giggle, then swat the other and giggle once again. I thought it was funny. I talked to her as she did it, said those are Mommy's boob, so on and so forth. I am a firm believer in the body being a natural thing, and not teaching children to be uncomfortable. Of course there are things you do only at home, and there are things that are not appropriate to do with other peoples bodies. But as far as her body, especially, if she wants to explore, I think it is completely healthy. It is after all, her body.
Sorry...side tracked....anyway...today......we were in the shower as always, when she decided to grab my nipple and pull. Very quickly she decided this was cool, and grabbed the other. ( in my opinion she was trying to decide which one she could stretch farther ) I immediately ( she is much faster than I am ) told her that hurt Mommy and she needed to be gentle. She let go for a moment, only to grab and pull again.
To this I asked....." Do you think Mommy is a cow?"
To which she simply replied...." Mooooooo"

This is a true story.