Smell from Anus. PLEASE HELP!

It has been about 4 months now. One day I played with myself (anally) and it ended up smelling bad afterwards. I suddenly became constipated and 2 days later, when I strained, the smell became more prominent. I was then constipated for two weeks, and when I did start going to the bathroom, my bowel movements were really pasty and smelled bad. This continued for an entire month, bouts of constipation and smelly bowel movements. But then the bowel movements became normal, but the smell never went away. I should add, that the smell WOULD GO THROUGH THE ROOF after the bowel movements, REALLY increase, REALLY BAD. Now its just there. Its kind of strong to others but I can't smell it, ever. I still get regular flatulence, and have complete control of my bowels. Sphincter strength is clearly not an issue?
Can the anus ever be partially open? I don't have any leakages.
But the smell does increase after bowel movements.
Other than the smell, I do not have any symptom at all. NONE. zero. Please help.

Things I have tried
-Probiotocs, Colon Cleanse,Baking Soda, Grapefruit seed extract.

Also, I do not even know if the problem is with the stomach or the rectum. I heard someone who had the same symptoms as mine got cured by overdoing on fennel seeds.
Please help me figure out what is causing the smell in my case Tweet