Hi 135505, well if I don't have a bowel movement for like 2 days, the smell begins to come out through my skin also and strangers can tell that I am constipated. But I guess smelling like you're constipated is better than smelling like you had a bowel movement and didn't clean up properly. The 2 things that I believe may be responsible for my anal fecal odor are hemmroids and fungus/bad bacteria.
In addition to the anal odor, I also experience incomplete evacuation. I remember getting penetrated in the anus very roughly and immediately afterwards, when I went to use the bathroom, all I passed out was blood. And the incomplete evacuation feelings I always had disappeared, and my anal fecal odor diminished significantly. So it seems I may have swollen veins (hemmroids) in my anus that busted during that sexua| encounter, leading to passing out blood afterwards and the incomplete evacuation feeling vanishing.
It may also be that the hemmroid is causing the anus not to close properly - explaining why I always have at least a faint anal fecal odor. And the reason why my anal fecal odor intensifies after a bowel movement may be due to bad bacteria/fungus from the hemmroids.