Do most men shave their pubic hair by their penis?

No: Contrary to your implied perception, shaving pubic hair is unhygienic. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex.

No, of course not: There is no need to shave pubic hair. The more people who shave their pubic hair, the more pressure there will be upon other people to also shave their pubic hair. Since there is nothing inherently abnormal about pubic hair, there is no reason to shave pubic hair. It's just a matter of fashions or fads, unless a person is having recurrent problems with pubic lice.