I didn't start to feel my baby hiccup til 33 weeks ish. But that can be different for everyone. As far as the feeling goes, the only way I can describe it to you is that you'll know right away that's it hiccups. Like its a consistent movement and you just know. Lol. I wondered before I ever experienced it, and you just know when it happens.
Just depends. I can't remember when I started feeling hiccups I want to so close to 30 weeks. And they feel like kicks but they're very close together and have a rhythem to them. Almost like a heartbeat.