The largest vein in the penis. Once the penis has become erect, the blue/purple vein becomes clearly visible.
by PMchoisi June 08, 2009
The large vein that travels the length of a cock. Instrumental in delivering blood from the central artery during erection.
My cock was so hard, my main vein was swollen with blood.
I saw my heart beat as the main vein of my cock pulsated with blood.
I saw my heart beat as the main vein of my cock pulsated with blood.
by Tony from the Lido September 21, 2011
by mickyxtee May 09, 2009
by Xeroman November 23, 2015
by Doc Evil July 24, 2003
Me: Yo, do you even rail the main vein?
12 year old on Xbox live: Yeah, fucker, I rail the main vein every day!
12 year old on Xbox live: Yeah, fucker, I rail the main vein every day!
by Blawkz February 09, 2015
to piss (=
by dongsaucer (= September 17, 2008