Frenulum breve, or a short frenulum, is a condition in which the frenulum preputii penis, which is an elastic band of tissue under the glans penis

Glans penis

The glans penis is the sensitive bulbous structure at the distal end of the penis. The glans penis is anatomically homologous to the clitoral glans of the female...

 that connects to the prepuce

Foreskin

In male human anatomy, the foreskin is a generally retractable double-layered fold of skin and mucous membrane that covers the glans penis and protects the urinary meatus when the penis is not erect...

 (foreskin) and helps contract the prepuce over the glans, is short and restricts the movement of the prepuce. The frenulum

Frenulum

A frenulum is a small fold of tissue that secures or restricts the motion of a mobile organ in the body.-In human anatomy:...

 should normally be sufficiently long and supple to allow for the full retraction of the prepuce so that it lies smoothly back on the shaft of the erect penis

Penis

The penis is a biological feature of male animals including both vertebrates and invertebrates...

.