Smoking tabacco is my answer.
1.) The process of ejaculation starts with : A testis will produce sperm cells. These sperm cells will travel through the vans deferens. The accessory glands (seminal vesicle and prostate gland) will produce a fluid that will be combined to the sperm cells that will be semen.
2.) The process of menstruation starts with: An ovary will produce an egg cell every month that will travel through the fallopian tube and will go to the endometrium, the lining of the uterus. Since the egg cell is not fertilized, it will not be remained to the lining. Instead, the endometrium that has many blood vessels will shed blood containing the egg cell and that is the menstrual blood.
(Sorry for the wrong grammars)
His muscles are getting stronger and have to break down to do so and that process hurts.
It would cause dangerously low glucose levels in the blood
