Good old natural sweat can be a turn on. As long as it hasn't been too long. I can't stand the smell of my sweaty underarms without deodorant, if I'm in a hurry, and forget. The natural sweat on my balls after sex, or a jack off session can be a turn on to me though.
However, that fishy smell (usually found on an unclean, uncut cock) is just plain nasty. I don't know how long, without a shower, it takes to get to that fishy smell but it gags me. What is more disturbing is that I am encountering it more than I ever have before. Are people just not showering anymore? Can someone, with an uncut cock, tell me if they know, about how long it takes(without washing) to get that fishy smell? Is this smell a combination of piss, sweat, and old cum? Just curious.