Let the good times roll, and kick, and punch

I finally figured out how to explain what it feel like to be kicked from the inside. Every book says, "It feels like gas bubbles." I have to disagree on some level. At first when I started to feel the baby kicking at 18 weeks it felt like gas bubbles. I was worried that crop-dusting was imminent. However, the further along I have gotten and the bigger the baby has gotten, the less it feels like gas. The best way for me to express how it feels is to compare it to a muscle twitch. It feels like an uncontrollable muscle twitch (the kind you get in your arm or leg). Does anyone agree with me?