'Frenulum.'
***** Frenulum, or, more accurately, the frenulum of the prepuce (foreskin), refers to the band of tissue under the glans penis (cock-head) in uncircumcised (uncut) men. It connects to the foreskin and helps contract it over the glans (cock-head) during an erection.
***** The frenulum is highly sensitive to gentle stimulation. Solo, stroke it slowly and lightly with lubricated fingertips. With a partner, lying or standing, gently and very slowly, rub your lubricated frenulum against your partner's frenulum whilst you deep kiss.
Always practice safe sex.
More information on the frenulum of the prepuce @ wikipedia.com
