Mine was very strange too, apparently- went undiagnosed for years, not for lack of trying on my part.
I'm pretty sure mine started about 1/2 way up the rectum- I had the most horrible vaginal/rectal pain for years. It literally hurt to breathe. I had a "lump" they could feel vaginally but they thought it was endometriosis and I even had numbing shots put in that area- they didn't work because it was the abscess. So then we're pretty sure that the physical therapy I had been going to for vaginal pain (manual and e-stim therapy) pushed the abscess back around my tailbone to the other side, where it formed another abscess and a fistula, which opened just at the back of my anus. I had a lump the size of a piece of chalk from my tailbone down. They STILL couldn't find the thing surgically and plugged the fistula so it just opened back up just inside my rectum. I continued with these surgeons until they finally found what I was talking about and my seton was placed and they also incised the abscess that was higher up in the rectum. That one healed (finally, it was amazing to not hurt there anymore) and my seton fell out a while ago. So I guess mine was up around the tailbone too- I even had a "tailbone distraction" at PT which made me want to DIE. This was all before they realized what was really going on. I'm still healing and not convinced that I'm all better yet, but my surgeon wants to wait a few months before we make any decisions. Said my surgery site has got granulized tissue there, which is a good sign of healing tissue... so that's my story in a nutshell. I was told over and over I was atypical, I was "zebras not horses" and that they still can't quite figure out what was going on with me... Let me just say it is NOT good to be unique in the medical field...