Lift your back.

Suck your ass like this.

And your stomach will get thinner.

. You must suck your stomach when you are standing.

Breathe through the abdomen. Abdominal breathing: fully inhale.

Exhale and spit it out (if you feel that your stomach is about to stick to your back, it means that you have finished exhaling). This will make the muscles in your stomach

solid

wired