The unique, warm feeling a surfer
experiences when they urinate
in their wetsuit
Wetsuit = Cold Weather = 'Damned if I'm going back to shore and unzipping my warm wetsuit and chilling my private parts when I can let loose and feel warm at the same time.'
It should be noted that this can have the unwanted side effect of attracting sharks.
Contributed by wertperch:
Urinophoria is also experienced by kayakers and canoeists. Or in a strict sense, anyone wearing a confining suit whilst immersed in cool or cold water.
External reference of surfer slang: http://www.geocities.co.jp/NeverLand/8882/surfinslang04.htm