When you are told by someone that something amazing just happened, but they won't tell you. You know how when guys are just about to get it in, they get all excited?
well, if they don't get it in, and they're still excited, they get blue balls. or it just hurts them a lot, because they can't release.
Mentally blue balled means that you got all excited and then didn't complete with the exciting thing/action.
Jane: OMGAH,Jenny! You'll NEVER guess who's transferring into our school next week. You are gonna FREAK the fuck out! OMG i could barely believe it myself.
Jenny: Tell me! Tell me!
Jane: Nah, chill.
Jenny: ...
Generally applied, failing to perceive something brutally obvious because you are too distracted by an insignificant detail. Specifically, failing to notice how disgusting the video "Two Girls One Cup" is because you are too distracted by how nauseating their blue eyeshadow is.
A phenomenon that occurs when listening to a sweet dubstepsong, and for one reason or another the song is cut off right before the breakdown, as the bass is about to drop.
Everyone at the party got dubstep blue balls because the neighbors shut off the power.
The phenomenon in which a normal conversation turns blue, becoming so riddled with sexual innuendo that it's rendered nearly impossible to steer back in a non-pervy direction. Every innocent comment starts to become a dirty double entendre, until eventually the entire conversation turns into a complete smut-fest from which there is no return.
Girl: Ah, who doesn't love stripper zombies in Portland? That'd go down like Jesus on a velociraptor.
Guy: I have to admit, when I first read 'go down'... I had rather blasphemous thoughts.
~ten minutes later, during which this term is invented~
Girl: Hmm, this Urban Dictionary thing is quite fun. Something for the annals of history.