They are the venae comitantes of the internal pudendal artery.

They begin in the deep veins of the vulva and of the penis and scrotum, issuing from the bulb of the vestibule and the bulb of the penis, respectively.

They accompany the internal pudendal artery, and unite to form a single vessel, which ends in the internal iliac vein.

The deep dorsal vein of the penis communicates with the internal pudendal veins, but ends mainly in the pudendal plexus.

This article incorporates text in the public domain from page 674 of the 20th edition of Gray's Anatomy (1918)