It's a nice start for something done on your phone. Maybe make the waist a bit bigger?

My gosh it's been a hell of a while since I made this first post. Looking at it now I'd say the person is doing the vacuum suction with the abdomen. Anyways drawing in general I haven't been able to do in years. Nevertheless I'm much appreciated with the criticism.

Oh sorry! I completely missed when this was posted!!! Hahahaha >_<