what happens is this; no matter how well you wipe your bum, small traces remain. when you begin to sweat, these traces combine with the sweat to form a slurry which is very abrasive ,irritating,corrosive,[ has been known to rot underwear ] ,and foul smelling. to much hair around the anus does not help. better to keep it trimmed or better still, shave it clean. next, when you have finished wiping your bum, wash it with a weak solution of sea salt and water. dry it well and see if there is any improvement .this worked for a friend of mine some years ago.

I worked with a guy many years ago who must have had this problem,.We worked on heating systems in very confined spaces. As you can imagine once the heat got going and this guy began to sweat the smell was something else! many a time I nearly got sick,and to get out for air. I though at the time he was just a dirty old sod who never washed. I dont have the finial answer to it but get it seen to or you,ll find your friends giving plenty of room. You,ll also find it very hard to find anyone to give you head. See about it soon Good luck. 8-|

I forgot to mention : forget about nylon underwear, only makes things worse.forget about g strings too. you need something soak up any discharge. stick to white cotton,and change them every day. stay away from coloured cotton,you dont know what the hell is in these dyes.