Many men, when they start restoring their foreskin, have questions about the frenulum. To answer questions about the frenulum, we must first consider what the frenulum does and how it works.
(click the pics to embiggen - NSFW)

The frenulum is a body part that connects the glans penis to the ridged band of the foreskin. The frenulum functions as a tether. It is a relatively inelastic section of tissue extending from the meatus to the ridged band on an intact man. The frenulum is connected to the inner foreskin by a web. The frenulum prevents the intact foreskin from retracting and fully exposing the inner foreskin, like it is on a circumcised man.

To understand how the frenulum works, consider your tongue. The lower portion of your tongue is connected to the floor of your mouth with a frenulum. The bottom medial portion of the tongue is tethered to the floor of the mouth. Without that frenulum, the tongue would be able to move fully back into the throat. With the frenulum tethering the tongue, you cannot swallow your tongue.

The penile frenulum also cooperates with the ridged band (often called the frenar band) and the dartos sheath to automatically extend the foreskin to cover the glans. As a tether, the frenulum has a tendency to pull the foreskin toward the glans. After this motion is started, the ridged band and the contracting dartos sheath finish the job of fully extending the foreskin over the glans.

Another function of the frenulum on your penis is pleasure. The frenulum is highly innervated with Meissner's corpuscles, which are fine-touch nerves. The Sorrells study showed that the frenulum is one of the most sensitive areas on the penis.

With that background, what does it mean for a restored man?

First, no circumcised man has his complete frenulum. Because the ridged band is excised during circumcision, the part of the frenulum that connects to the ridged band is also removed. Depending upon how Dr. Butcher performed the circumcision, anywhere from a little to a lot of the frenulum may have been excised. Because the structure that makes the frenulum work as a tether is partially missing, the tether function cannot be restored. We must rely upon the dartos sheath and foreskin length to cover our glans.

Then there is sensitivity. As for sensitivity, it varies from man to man. Some men report that the frenulum remnant is the most sensitive area on their penis. Others report that the corona is the most sensitive. Regardless, restoring will dekeratinize the inner foreskin and glans after they are covered by the restored foreskin. Dekeratinization will return the penis to its natural and normal sensitivity level.

Every circumcised man has at least part of his frenulum removed. The part that connects to the ridged band is removed with the ridged band. Some doctors, for some warped reason, also scrape or excise the rest of the frenulum, or at least all that is visible. This is what most likely happened if the ventral (bottom) side of your penis is as smooth as the dorsal (top) side. Fortunately, some men report that, as they restore, the tissue where the frenulum should be changes and begins to look like a frenulum remnant.

My frenulum is surrounded by scar tissue. Based on reports from others, I think that when Doctor Butcher circumcised me shortly after birth, he used forceps to separate my foreskin from the glans. Those forceps must have pinched my inner foreskin, damaging the sensitive tissues. Because the foreskin is fused to the glans at birth, the bond between the foreskin and glans must be broken forcibly. If the doctor is not careful, the surface of the glans can be damaged and pitted. In my case, the tissue next to my frenulum shows signs of trauma. Before I began restoring, the area surrounding my frenulum was painful to the touch. I had islands of scar tissue surrounded by reddish/pink tissue, which I now know was the mucosal tissue of my inner foreskin remnant. The islands of hard scar tissue pinched the inner foreskin when the scars moved. Fortunately, restoring my foreskin has loosened up that scar tissue and I only occasionally experience pain when I touch the area near my frenulum.

Does it matter how much frenulum remnant is left? Maybe, but probably not to a great degree. Now that I have enough foreskin for the gliding action, I notice that my penis feels really good. But, I could not tell you exactly what part feels the best. During masturbation and sex the restored foreskin rolls up and over the corona and glans. The rolling motion stimulates the Meisner's corpuscles in the inner foreskin remnant, the frenulum remnant, and the corona. It is a combined stimulation that all happens together like nature intended. And, it feels a million times better than my circumcised penis ever felt.
 

Additional Links:

• For intact foreskin frenulum pictures, see Celebrating Foreskin - Frenulum posts
• Frenulum page at Foreskin.org, a collection of close-up photographs of the normal, natural, intact adult male foreskin