I didn't realize this was a thing. Last night I was in bed reading with my hands propped on my belly, right over where the baby's back/butt were sticking out. My book started rhythmically bobbing up and down and I looked down and could see his back pushing against me and pulsing pretty quickly. It was definitely not hiccups because I feel those a lot, and this was much quicker and more shallow. I was worried for a second that something was wrong, then googled, and apparently this is fairly common. I called H into the room and he could see it too. The baby stopped shortly after he put his hand there, but glad he got to see it