For a long time now, I have been observing a small tube kinda skin popping out of my shaft before the starting of penis head.It has something black on its opening and when i stretch the skin, i actually see the tube being blocked by some strange kinda stuff with something black at the opening.When i pull the stuff out thru my nails what I see is that the tube has opened and now has nothing in it.I try to squeeze it but nothing comes out though I see redness in it. Is this a route to bloodstream?? what is it exactly??