I have a 14 yr old daughter who likes to constantly rub my belly! Lol I know it's not the same but still quite annoying, I had to tell her to knock it off and give her designated belly rub times. I know your son is very young but maybe if you explain to him that it hurts you, he'll ease up a bit.
Yep me too. I'm 31w2d and my 2&1yr old boys climb on me all the time. Feels like my stomach stays sore.