belly rubs

So...I'm 17 and decided it was time for me to get deflowered. I met this guy that I really liked, and we mutually agreed to have sexual intercourse. I was really nervous as this was going to be my first time and I didn't really know what to expect. When we had the sex he rubbed his tummy in a circular motion the ENTIRE TIME! I'm just wondering if this is normal. We had sex multiple times after this and he continued to do what I call the "Santa Rub". Am I missing something should I be rubbing his belly, does he have a fetish, is he hungry, does this stimulate pleasure? I googled this but could not find anything. HELP!!!!