My little guy gets so raging angry for a good 5 minutes after tummy time if I don't end it at the right time!! If I wait like a second too long, he gets so angry. I try to do 10 minutes at a time after each nap. He's probably only getting on average 30 minutes a day but he really really hates it! He gets frustrated when it's on me at a slight decline, he gets frustrated when I prop him up with a rolled up towel or boppy pillow, he hates it when it's flat on the floor or my bed. No toys, mirrors, or happy faces can distract him from his pissed off mood, lol.... I bought a water mat and he really hated that..... I think he's trying to roll over but he's not doing so well with rolling over. It took us quite awhile to get up to 30 minutes a day, and I'm sure he's not building the strength he needs.... He doesn't seem as strong as other babies his age.... Does he look like he's progressing ok? He'll be 4 months on the 21st....