Sexual anatomy that’s typically called male includes your penis and scrotum (external male genitalia) and internal reproductive organs like the testicles.
What are the external parts?
Your penis and scrotum are the two parts of the male (or what’s typically called male) external sex anatomy (outside your body).
Your penis is made of 3 layers of spongy tissue. When you get turned on, blood fills these tissues. This makes your penis get harder and stand up, which is also called getting an erection or hard-on.
The average size of an adult erect (hard) penis is 5 to 7 inches long. The size of your penis when it’s flaccid (soft) doesn’t have much to do with its size when it’s hard. Some penises get much bigger when they get hard. Others stay pretty much the same size.
About half of all penises in the US are circumcised, and half are uncircumcised (still have foreskin) — so both types are common. Some people call circumcised penises “cut,” and uncircumcised penises “uncut.”
Every penis looks a little different. For example, some curve like a banana when they’re hard. Others are straighter. All penises have the same parts though:
Your glans is also called the head or tip of your penis. The opening of your urethra is here. This is where pre-ejaculate (precum) and semen (cum) come out of, and it’s where you pee out of. For many people, it’s the most sensitive part of the penis.
The shaft of your penis extends from the tip to where it connects to your lower belly. It looks like a tube. Your urethra is inside the shaft.
The foreskin is a patch of skin that covers and protects the head (AKA glans). When your penis gets hard, the foreskin pulls back and the tip is exposed. Sometimes foreskin is circumcised (when a doctor surgically removes your foreskin) soon after birth, so not everyone has it.
The frenulum is where your foreskin meets the underside of your penis. It looks like a small V just below the head. Usually part of it remains after circumcision. And for many people, it’s very sensitive.
Other external parts include:
The scrotum (AKA ballsack) is the sac of skin that hangs below your penis. Your scrotum holds your testicles and keeps them at the right temperature. If it’s too cold, your scrotum pulls your testicles closer to your body. If it's too warm, your testicles hang away from your body.
Your scrotum is covered with wrinkly skin and hair. Your scrotum can be big or small, have a little or a lot of hair, and vary in color. Some people’s scrotum is larger on one side than the other.
The scrotum is super sensitive, so any hitting or twisting is extremely painful. But many people like having their scrotum gently touched during sex.
The anus (AKA butthole) is the opening to your rectum. The anus has lots of sensitive nerve endings, so some people experience sexual pleasure from anal stimulation.
What are the internal parts?
The internal parts of male sex anatomy are made up of:
The testicles (AKA balls) are 2 ball-like glands inside your scrotum. They make sperm and hormones like testosterone.
The epididymis is a tube where your sperm matures. It connects each testicle to each vas deferens. And it holds your sperm before you ejaculate (come).
A vas deferens is a long, narrow tube that carries sperm from the epididymis to the seminal vesicles when you ejaculate (come). There are 2 of them — one connected to each epididymis.
Seminal vesicles are 2 small organs that produce semen, the fluid that sperm moves around in. They’re located below your bladder.
The prostate gland makes a fluid that helps your sperm move. It’s about the size of a walnut or golf ball. The prostate gland is sensitive to pressure or touch in a way that many people find pleasurable.
The Cowper’s glands produce a fluid called pre-ejaculate or precum. This fluid prepares your urethra for ejaculation (coming). It reduces friction so your semen can move more easily. The Cowper’s glands are under the prostate and attach to your urethra. They’re also called bulbourethral glands.
The urethra is the tube that carries urine (pee), pre-ejaculate, and semen to your urethral opening and out of your body.
The cremaster is a muscle that moves your scrotum and testicles closer to your body. This happens when you’re cold, you’re aroused, or when someone touches your inner thigh.