That is hiccups. The cutest thing ever. It totally feels like a muscle twitch to me. Sometimes I can tell that my little guy gets mad at his hiccups because he'll kick really hard :-) my little girl used to get them constantly, even after birth
Im 29 weeks and yea thats wat it feels like. Except i knew it wasn't that cause there heartbeats are super fast lol.
When my baby gets the hiccups it feels like a heartbeat.