Explanations...

So, does anyone out there have any really great, simple, yet adequate, ways to explain the menstrual cycle to a 2 1/2 year old? We have discussed that it is not painful, only women get it (as opposed to men and children) and it is blood. I wonder what she's going to tell her Sunday school teachers this week? Or better yet, what is she going to mention to Grandpa and Grandma at the family gathering this weekend. Oh gosh! How funny!