Small hard white bump on penile shaft, what do I do?

[Purpleurple]

It's removable, and leaves a small bump with a hole in it that bleeds a very small amount before stopping. It's like a hard white pimple, I can grab it with tweezers, and it usually gets to be about the size of a grape seed if left alone for a few weeks. It sits at about the middle of the shaft, and when I try to pick the whole thing up it doesn't hurt so I'm guessing that it's not attached to the cartilage of my penis (thank god).

When not pulled out, it usually grows large enough to look almost like a mountain; with a little point at the top which sometimes catches on my underwear.

I don't know what it is, or what to do, so I've tagged several things that I've seen that it possibly could be.