“Where do you push on your stomach to release gas?”

This doesn't really work. Firstly, it may not gas that you are experiencing but if it is gas then there is no way to move it through the GI tract by pushing on the abdomen. Gas actually moves quickly through the GI tract naturally and should be released as flatulence. Reduce carbohydrates in the diet to reduce gas in general.

Normal bowel activity causes release of gas by burping or farting as part of normal peristaltic activity - Activities like Yoga and Walking aides and helps improve and maintain bowel movements - Carminatives like mint and ginger tea can help as well. Please do not attempt any mechanical ways of pushing the abdomen to expel gas. Please make an appointment with your PCP if you need to have this evaluated. Conditions like Bowel obstruction need emergent evaluation and you may need to go to the ER.

What I find works best for gas is to lay on my back and cup my hands then lightly making drumming motions all around.
If it persists, then taking a walk helps.