A half boner, or semi-erection where the penis is not yet completely erect, but not completely flacid.
Dude, that super hot chick gave me a hug and before I had any idea I was sporting a mean sem-dog.

Can I get a sem-dog for my Rem-Dog. (Said when you want your friend Remy to get some ass).
by Schloss January 12, 2006
to have a semi erection
'i was just chillin with a semdog' 'i got a semdog at work today'
by muscle shark August 09, 2009

Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from daily@urbandictionary.com. We'll never spam you.

×