According to Wikipedia (Ad Aged, personally, wouldn't know)blue balls is a slang term for a temporary fluid congestion in the testicles and prostate region caused by prolonged sexual arousal in the human male. It is often accompanied by a cramp-like ache of prostatic congestion and pain/tenderness of edema of the testes. While the term is usually applied to men, the female homologue is usually referred to by the more general term "pelvic congestion," or "pink ovaries."
Blue balls, I might add, is also what putative internet start-ups give you when they promise to "premiere" on a certain date, or promise they're coming soon and then they miss every deadline. Specifically, I'm irked with Firebrand, a company I mentioned a dozen or so posts ago in "Is this the new "new new thing." They claimed to be debuting on October 22, and took out full-page back covers announcing their debut in advertising trade pubs. So far, they're still "coming soon." Another company "coming soon" is twine.com, supposedly a company at the van of the semantic web (whatever that is) or Web 3.0 (whatever that is.) Also, Boeing who have missed all their Dreamliner deadlines. Also, certain advertising agencies (especially interactive ones) who have been redesigning their for-shit web-sites for literally years.
OK. This is pretty simple. If you make a promise, keep it. If you can't keep it, publicly eat crow and then get it done. Otherwise you lose people. Or, you piss them off.