The coronal ridge is the area just below and around the penis head.

This part of the penis is very sensitive to touch and oral stimulation.
The Coronal Ridge and The Male Sexual Excitement
The coronal ridge together with the frenulum (the small fold of skin located on the underside of the penis head) is the most sensitive part of the penis.
When this area (including the frenulum) is stimulated, either via self-stimulation or oral stimulation by a woman, it heightens a man’s sexual excitement and hence leads to an orgasm.
During Oral Stimulation… Fellatio
Should a woman kiss the coronal ridge gently, and then twirl her tongue around the penis head, focusing more on rubbing across the coronal ridge and the frenulum… the man will experience the most pleasurable blow job ever.
Also, should a woman grasp the man’s penis at the base, then, squeezing lightly, slide her hands up the penis and over the coronal ridge, then back down again… this will feel really pleasurable for the man.
Focusing on rubbing across the head of the penis will give a man the most pleasurable blow job experience ever.
The Coronal Ridge and Premature Ejaculation
There is a sex therapy technique where a man squeezes the head of the penis in order to prevent ejaculation.
This technique is known as the squeeze technique.
It has the effect of delaying ejaculation and prolonging intercourse.
With this technique, the man squeezes the head of his penis when he feels that he’s about to ejaculate. Or he may ask his woman to do it.
Here, the man firmly grasps the penis on the coronal ridge between the forefingers and thumb… and then squeezes hard to prevent ejaculation.
He places his thumb on the head of his penis (on the coronal ridge), and his forefinger behind the penis head (on the frenulum) and gently applies pressure against the urethra (the tube that carries semen out of the penis) until the urge to ejaculate subsides…
So, there you have it…
…the coronal ridge.