It happened to me the 2nd time, I remember the same thing but it was long ago.
When I woke up with erection, I wanted to pee. So, I was standing in the bathroom waiting for a hard-on to go away... I noticed some rather big bump, like a huge corn kernel. It was prodruding where the "neck" is, right below the head but on the top and to the side. It was very hard, under the skin, and did not have a smooth top, it was a bit asymmetrical. I got really scared but hard-on went away, I *****d. Then I was unable to find that bump there at all right after. I made myself hard again, it was totally gone, not even a hint. Then I remebered that something like this happened maybe a year ago, don't remember when, since it went away, I forgot about it. Now it kind of came back and I remembered.
A week went by, I have not seen it since then.
Is it something to do with the way penis gets filled with blood and somehow over-fills some parts of it?
Is it something that I should talk to a doctor about, that is, if it is a sign of something that is preventable?
I don't really worry about it but I feel like I should ask.