hands off!

I alright ladies I need some help with with everyone touching my tummy. I'm only 16 weeks hardly showing so I know it's only going to get worse. I need a nice way to stop ppl from touching!! My MIL and FIL especially can't keep their hands to theirselves, they are doing it out of love I know, but I can't stand it. She even does the sign on the cross on my stomach and prayes it makes me so uncomfortable!! I know no matter what I say it is going to offend her but I'll try anything at this point... any tips??