Mainly through chest enlargement and chest muscle exercise to achieve the effect, weightlifting, dumbbells, horizontal bar and so on. They are all good exercises for the upper body, but considering that you are MM, because these exercises are easy to make the arm muscles obvious, I suggest you do such simple exercises:

1, tightly clamp your arms forward, including the back of your chest arch, until you can't contract;

2, slowly open your arms and expand outward until your arms can't expand backwards;

3. Pay attention to breathing during exercise;

4. Do it 50- 100 times every morning and evening, and you will see the effect every month.