I have a lump on the top side of my penis (other side of the shaft), it is roughly in the center and to the back end, and can be seen beginning near my pubes. It feels the same as a vein, however it is much larger, and I cannot directly see it. It is about an inch long when my penis is non erect. When it is erect, or the blood in my penis is restricted it lengthens greatly and is very visible. Also there are small white bits around the bottom of my penis head. I don't know much about this part of the body...

I am eighteen years old and had these for at least three years now, I masturbate regularly and I am a virgin. Any information would be apprectiated.