The penis is used for two jobs, peeing and sex. When your penis is erect, you can’t pee easily because a muscle closes the bladder off. The shape of an erect penis varies. It usually curves upwards slightly, and may point to the one side. Erections (hard-ons, boners, stiffies) occur in males of all ages, including babies and old men).
Erections can come and go without warning. They can happen at a moment’s notice, sometimes in embarrassing circumstances. And they can vanish just as easily. Alcohol can cause an erection to droop. So can fear of being laughed at, of coming too soon or of causing pregnancy.
During an erection, more blood flows into the penis than usual and less blood flows out. This makes the penis becomes larger and harder and it stands out from the body.