You touched me where?

I know it has been several days since I last posted. i have been in San Diego since Monday morning. A friend has been in the hospital so I've been spending most of my time there. However, she came home this afternoon. And her coming home this afternoon is what brought about my the incident for my post today. She is still on bed rest but she also needed some medication. So I went to the Long Drugs. As I went in I past a mother and her son, approximately 3 years old. The little boy was trying to go in through the out door and so the mother let me pass by and go on in. I walked up to the pharmacist counter and i was standing there hunched over filling out the information form when suddenly I felt a pair of little hands rubbing my butt cheeks. I turned around and it was the little boy. I guffawed out loud. Meanwhile the mother horrified. Then she had to try and explain to the little boy that even though I was laughing and then when she realized I was not going to get angry and sew she was laughing that it was not funny to touch someone there.
Now here is what I want to know, what was it about my butt that incited this little child to just run up and start rubbing it? I know it is perky but I've never had anyone of any age just run up and start rubbing it. (Alright I guess that isn't completely true, but never a total stranger. Okay that probably isn't completely true either--but it has never happened in the Long Drugs.) Or did it look so plump that the little boy thought it was a pair of punching bags or pillows? I guess I'll never know unless it starts happening often. I'm going back to the Long Drugs tomorrow, so we'll see if it is about the Long Drugs.

I'll let you know.