A condition in which the small size of the preputial opening of the foreskin (specifically the frenar band) prevents the skin from retracting behind the glans.

See Inner Foreskin

The natural “drawstring” at the tip of the foreskin.  It's primary function is to keep the foreskin forward of the glans penis. It is comprised of dartos muscle, which is involuntary smooth muscle.

Nearer or nearest to the center (of the body); opposed to distal.   On the penis, it would typically refer to the base of the penis.