"Blue Balls" is a slang term for Vasocongestion. It is a deep, uncomfortable ache that appears as the result of pelvic congestion (when more blood and lymph flows into the genitals during sexual arousal than out), especiallywhen it remains in the genitals for an extended period of time. If there is no release through <a href="http://www.coolnurse.com/orgasm_male.htm" target=_blank>orgasm</a> and ejaculation, the area remains engorged, and without any outflow, men may feel slight discomfort in the testes.
Cramp-like ache, pain or tenderness in the testes after sexual arousal.
Ejaculation does alleviate blue balls. If there is no orgasm, however, the erection, blood flow and aches will subside eventually.
<b>Ask your Physician</b>
Vasocongestion is not harmful, but if the condition lasts for hours or days after you've stopped being sexually aroused, then see a health care professional.