Question. My little one still hasn't learned how to roll over and doesn't even try. He's always trying to sit up though.…

Question. My little one still hasn't learned how to roll over and doesn't even try. He's always trying to sit up though. I do tummy time with him but am I doing it wrong? I usually pick him up after he starts really fussing and doesn't hold his head up anymore. I do it with and without the pillow in the picture.