So, as my subject line states, I have a mysterious bump. I'll summarize events as best as possible:

Last Saturday my fiancee was out of town. When I'm alone in bed, half-awake, and horny, I sometimes find myself grinding against my mattress a little bit (which sometimes results in an orgasm.) So, that happened on Saturday. Sunday I got up to pee, looked down, and saw one side of my penis was very swollen. I figured I'd give it some time to go away.

My fiancee got back and we had some "reunion sex" after her time away, but I noticed as I put on the condom it halted when I got to the swollen part and I had to roll it over the bump. A day or so later, I was feeling the area (the swelling had gone down) and it was replaced with a hard bump. Sex was a bit uncomfortable for me so we decided to abstain for a night, and it seemed to improve a little bit, but not to my liking, so I made a doctor appointment.

The weird thing is, the bump comes and goes. It seems to show up at night, and in the morning, and after I have sex, but throughout a typical day it's not there. So when I saw the doctor it was the afternoon and there was absolutely no bump at all. But I just checked and it's there again. My doctor assured me that it can't be cancer because cancer doesn't come and go, and suggested it could be something like a zit - but I also know zits don't come and go either (at least on my face they don't.)

The doctor brought up the possibility of an STD test but that's not something I feel is necessary.

My current view of it is to give it a few more days since it seems to be improving, and since my doctor didn't seem to think it was serious, but I was just wondering if anyone else has a similar experience.