This probably very unique and quite strange but here goes nothing. When I was younger my skin would dry out horribly in the winter and let this rash/irritation/whatever spread on my arms and the tops of my hands. At first I needed special cream to kill it with fire, but as I got older I prevented the spread from even beginning with moisturizer applied regularly. Before I learned all this, i basically looked like my skin was a disgusting fiery red of nasty times. The point of all the above is to explain as best I can what I had on the tops of my hands, because when I was showering one day, realized that hot water made the dry itchy skin feel good, especially the hand tops. The hotter the water, the better it felt. This got to the point where I had the hot water at full blast, pouring steam and scalding water straight into my hands. I am not into the whole pain=pleasure thing, but there was something about that scalding water blasting my skin that created this absolutely fantastic feeling. There was nothing sexual or even orgasmic about it, though orgasms are the closest I have ever come to the level of amazing I felt. I eventually had to stop doing this because it made the rash worse. I have never let my hands get that bad again, considering it made me look one level below a leper, but my hands tingle with just the thought of it.
tl;dr-No one will read this but scalding hot water on a rash felt insanely good, I just felt like being overly verbose.