NRB 

Short for "No Reason Boner." Generally, an erection that has no inherent cause other than a young man's hormones going crazy. The term is usually used to clear sexual tension when other prepubescent boys notice a bulge originating in your crotch area.

"For Christ's sake Dave."

"heh heh...::nervous laughter:: talk about a NRB. I sure hope the 10th graders don't see me."

NRB by desperryado October 3, 2005

NRB 

Noun. NRB ( No Reason Boner)
This is what all male humans experience spontaneously, occuring from the early ages of adolesence to even in some rare cases senilty. NRB can attack men unkowningly, silently, and suddenly causing possible embarassing situations or even discomfort.

Zach was wearing basketball shorts walking to third period when he suddenly got an NRB and caused laughter and jeering from students around him.

NRB by Ktang April 20, 2006

NRB 

No Reason Boner

I was sitting in class when I got a huge NRB.

NRB by Joey February 26, 2003

NRB 

No Reason Boner.......

Phil cracked an NRB in class.

NRB by Mad Snake August 28, 2006

NRB 

A No Reason Boner, or an erection that seems to appear from no where. Lest it be in school while doing calculus, in church, or while watching a Pepsi ad. It may not have any meaning at face value, but you know some where in the dark corners of your mind you were thinking about how hot it would be if Jesus titty fucked a differential equation using Pepsi as the lube.

Bro 1: Dude I got the gnarliest NRB last period. I have no clue why I even got hard.
Bro 2: Sure..."No Reason" my ass.

NRB by Zehn Fjire Tjie June 14, 2015

nrb 

no reason boner. when you get an erection for no logical reason.

a: why do you have your hands in your pockets when you could be playing catch with us?
b: nrb, man...nrb.

nrb by phlipnrip November 29, 2009

NRB 

NRB stands for No Reason Boner. Obviously, it's a boner you get for no apparent reason. It can happen at any moment in time.

I was walking to the front of the classroom when ... SHIT! I got an NRB

NRB by Some fag with no balls June 26, 2009