is there a pressure point on the ribs??

Last night at my Halloween party I was getting physical with a guy. When we were kissing and he was sucking and biting on my breasts he kept intentionally pressing his thumbs hard into the side of my ribs and asked does that feel good. It hurt. Like bad. Not good at all so I told him so he stopped but it confused me. He seemed to do it right when he thought I was gonna cum. Anyone experience this before? Or can explain to me what he was trying to do?