Just my two scents - I had a spirited first born that HATED tummy time. He literally screamed after about 30 seconds, so I didn't do TT on the floor with him. Yes, I heard about it from my pediatrician who said I should do it anyway, but he hated it, so I wasn't going to let him sit there and scream just becuase someone said it would be good for him. He would lay on my tummy, and sometimes we did that, and he got lots of sitting (assisted) time. He learned to sit, crawl and walk exactly on time anyway. I wouldn't force it on your lo if they scream. They are trying to tell you something, and you should respect what they are saying. Don't want to break that trust, right? The tip about the rolled up quilt or boppy pillow under the chest is a good idea, though, and definitely worth a try.