Photography by Unsplash 

Think you know what’s below his belt? Truth is he may not even know the finer details of his penis. 

An anonymous man investigates…

I thought writing about my below-the-belt anatomy would be easy. After all, I’ve had access to the equipment for 29 years. But the very first expert I spoke with told me something I didn’t know: “There’s a difference between ejaculation and orgasm,” says Edward Ratush, creator of lovelifemd.com. There is? And the more experts I called, the more I learned. Three kinds of erections? Guys faking it? A male body part called the raphe? Once my head stopped spinning, I put together this explanatory guide to a man’s twig and berries. Get ready to teach the guy in your life a thing or two about what he’s made of.

The Big Fella: The Penis

The penis is far more complex than the fresh Polish sausage it resembles. At the top is the nerve-packed, helmet-shaped head called the glans. The thick, rounded rim of the glans is the corona. Right below the point where the corona curves up (on the side of the penis facing you when it’s, er, happy), you’ll find an ultra-sensitive ridge called the frenulum. This stretchy band of tissue is attached to the foreskin of an uncircumcised penis. Your man sports a tailored turtleneck? His frenulum’s only function is to register good vibes.

Moving down, the bulk of the shaft is made up of corpora cavernosa, two columns of spongy tissue that fill with blood to produce an erection. Similar tissue composes the corpus spongiosum, which surrounds the urethra, aka the handy hose that transports urine and sperm from their respective sources to the opening at the tip of the head.

Read More: How To Be A Penis Whisperer

Apply Pressure

Yes, it all feels good when handled, but a discerning touch goes a long way. “The upper areas – near the head – respond to friction,” says Ian Kerner, sex therapist and author of He Comes Next. “The lower parts – nearer the base – respond to pressure.”

To provide the perfect combo (not that you asked): During foreplay, tightly encircle the base of the penis with your fingers. The pressure restricts blood flow out of the shaft, making his erection harder and delaying orgasm. Supply friction at the head with your mouth or other hand and – ta-da! – we promise to take out the recycling for a whole month.

The Boys

The sperm and testosterone factories known as testicles roll around in that wrinkly sack called the scrotum. When it comes to balls, size matters – to a point.

“In general, the larger a man’s testicles, the higher his testosterone level and the more sperm he’ll produce,” says Harry Fisch, director of the male reproductive centre at New York-Presbyterian Hospital/Columbia University Medical Centre and author of The Male Biological Clock.

But as long as they’re walnut size or bigger, they should get the job done. To boost your partner’s reproductive health (and maintain his dignity), tell him to avoid super-tight spandex and lengthy Jacuzzi sessions – too much restriction and/or heat throws a wrench in the works.

Read More: The 4 Most Dangerous Sex Positions For His Penis

Gently Does It

On the pleasuring front, be gentle. “It’s more about stimulating the scrotal skin than the actual testicles,” Kerner says.

To send a shiver of deep and lasting gratitude through his body, locate the raphe, the central line that runs down the middle of his scrotal sack, and trace it with your finger or tongue.

The Nut Tugger

Surrounding the sac of each testicle is a thin layer of brawny flesh called the cremasteric muscle. Designed to help keep his cojones at the ideal sperm-producing temperature, this sucker draws the testes toward the body when it’s cold and lowers them when it’s hot. It’s also responsible for what’s known as the cremasteric reflex. Like your lower leg popping up when the doc taps your knee, the cremasteric contracts when you stimulate the insides of our upper thighs. It doesn’t necessarily turn us on (unless you’re holding a little mallet and dressed as a nurse), but it does let you play with our goods in a fun new way.

The Space Between

Inching farther down, the perineum is that smooth runway of flesh between the scrotum and the anus. In spite of the small army of nerve endings stationed there, not all of us want this border crossed.

To gauge your guy’s interest, go slow. During foreplay or sex, begin by gently cupping his testicles. Slide your fingers down and graze the area, then apply gentle, upward pressure. If he doesn’t jump a mile, keep going. Gradually increasing pressure – you can switch from fingertips to knuckles if he’s really into it – may indirectly stimulate his prostate gland.

Read More: What Should You Do If He Has A Giant Penis?

The G-Thing

Tucked just below the bladder is the chestnut-size prostate. This gland’s main job is to release a slightly acidic substance that, combined with fluid from the seminal vesicles and sperm, makes semen.

Guys may jet to a very happy place when you stimulate the prostate –some sex experts even refer to it as the male G-spot. That said, to get to it directly, you have to sneak in the back door – not everyone’s idea of fun. So, um, stick to the space between unless we say otherwise.

The Baby Makers

Though dispensed in a few enthusiastic seconds by the penis, it takes about two and a half months to cook up the hundreds of millions of sperm in the average ejaculation.

After sperm form in the testicles, they migrate up to the epididymis to continue developing, says Dr. Stephen Jones, vice-chairman of the Glickman Urological and Kidney Institute at the Cleveland Clinic and author of Overcoming Impotence.

Fully formed sperm then travel through the vas deferens – the long, thin tube that gets snipped during a vasectomy – and swing by the seminal vesicles, where they mix with a fluid that helps form semen. When a man nears ejaculation, the prostate adds its own fluid to the semen, which then taxis the sperm through the urethra on its way to the door. Before it exits, though, the pea-size Cowper’s glands near the base of the penis clear the hallway – they secrete a substance to flush urinary residue from the urethra. And finally, after all that endless preparation, comes the euphoric moment we’re always waiting for.

So now that you’ve got the penis intel, what about your important bits? Here are a bunch of things you probably didn’t know about your clitoris.

This article was originally featured on www.womenshealthmag.com