J.B.
my daughter was always on her tummy and rarely on her back (i didnt want her head to be flat either). if my daughter was on the floor 8 times out of 10 she was on her belly. i think it helped a lot with her head control, strengthening her back and aiding her to crawl early. my daughter was sitting alone and crawling by 4 1/2 months. i think it was from all the tummy time. just watch your daughters cues if shes getting fussy on her tummy put her on her back if she doesnt want that then try the swing or bouncer.