question for harassment

Hi:

I just had one incident happened two weeks ago, after that, I am thinking about it. Here is the fact:

After lunch, I walked back with an indian collegue, we were talking and sometime making jokes, then I remember we were making jokes about losing weight, he is a medium fat guy, has some fat on the belly, I recently lost some weight, he said that, then accidently touched my belly, acts like to feel how much fat I have. Is this considered sexual harassment? I don't feel good about it after that. Do I need to file a complain?

Thanks for your suggestion.