The first time it happened, my son was 4 months old. My husband was changing his diaper on our bed and turned his back for one second. The next thing he knew – BANG! – our son was on the floor, crying. I rushed into the room, and by the time I got there, my son was totally fine, lying on his back, kicking his tiny legs around, looking up at me, like, “What the heck just happened?” He broke into a gummy smile when I picked him up, so I knew he was fine. But I wasn’t.