Hi, I had unprotected sex six days ago, and in the fourth day when I had sex again there was a stinging/itching sensation inside the tip of my penis. It occurred in the middle of sex and right after I had accidently slipped out. Then after several minutes it stopped and I was fine. Now, two days later I am noticing it coming on every once in a while. None of the following have occurred; rashes, redness, erectile dysfunction, burning when urinating or ejaculating, lumps, or anything else. Just a slight sting/itch. What could it possibly be?