Hi. I recently started having this problem as well. Initially I thought it was because of my occasional constipation where my buttock gets sore due to force when I pass my waste; but one week I noticed the odor appeared even though I wasn't constipate at that time, so I started to do some online searches to see if I could find a solution. I did not find a solution so I started doing some brain-storming; I knew this wasn't a normal occurring condition...I did not have this problem all along, so something must be wrong. Finally it dawned on me that it must be some kind of infection or fungus that has developed in my anus (most likely from moisture and/or the warm climate), so one night I decided to use the only anti-fungal cream that I had in my house at the time, Lamisil. Lamisil is an anti-fungal cream for athlete feet and other superficial skin fungus. I started using it on my anus according to the instructions for one week, and to my joy and happiness, I was completely rid of the odor and the occasional itching that accompanied it at times!
Please note that any prescribed anti-fungal cream may do the job equally fine, but these creams are for external use only, and should not be inserted inside the anus or vagina.
I am sharing this with every one who is suffering from this problem simply because I know how embarrassing it is. Some people tend to ridicule other people when they are suffering from a condition; some of us never know what it is another person is feeling until we find ourselves in he same position. We all need to remember that we are all humans and sickness is not confined to just one person, or a group of people. Let's all help each other...you never know when your time will come...I didn't know that I would be humiliated in this way because I am very strict and self conscious when it comes on to my personal hygiene.
Take care and God loves you!