I felt like a thumping heartbeat kind of feeling around 18w
with my first it was like a butterfly, a little fluttering feeling very low kind of by my bladder. As he got bigger it was like little bubbles were popping. With this one I never felt the flutters just the bubbles always in the same area.
For me it first it felt like gas bubbles, then the next week it felt like a slippery fish swimming around in my belly...