DS is coming up 8 months, all the other babies I know are sitting unsupported now, and mine isn't. I know - shouldn't compare, but I'm worried. He can do it, but never tries, if I put him sitting down he wriggles so much he falls over, but he will sit on my lap unsupported. Trouble is he gets bored v easily playing on his back / tummy now. He has a bumbo but can climb out of it, same with inflatable ring. help!