My son is also 16 wks old n he always sits on my stomach as if we're his couch to get comfortable to play with toys or my phone, or he'll hug me n kiss me n is on top. He's heavy fr bby n myself but I gv my 16 month old the attention he wants n needs.
I wrk at a nursing home and one of the residents kicked me in the stomach twice I was sent to the hospital by my boss n was monitored fr four hrs n everything was ok. I was cramping, but no bleeding, not water leakage. So I came back to wrk l, im still full time n 30 wks. I think u'll be ok too. :)))
You ok the cramping ain't from the hit he ain't that strong
Your baby will be fine..there is sooo much water around him / her I don't think a 16 month old could hurt the baby.