cluster of small-stud-like thing under foreskin
I had a sex with a guy. When I sucked his dick, I found out that he has a cluster of very small stud-like things around the groove of his penis. He said he had been like that since he was kid. The stud thing looks like part of penis, not blister or lump. but never saw that before. I hope that you can explain whether I should have sex with this guy again.
Your question is a bit difficult to answer because neither of us have enough information to determine what the growths on his penis are. Many men have small bumps or growths on their penis that are not related to sexually transmitted infections, but may be small cysts or fibrous tissue (which are harmless). If it is true that your partner had these growths since he was a kid, then you probably have nothing to worry about. If you feel at all uncomfortable trusting your partner, then I'd recommend that you use condoms for oral sex. Using a condom for all contact will relieve you of making the more complicated decision of putting your health in his hands.
You can take a look at some pictures of common STDs at "What do the symptoms of STDs look like?" (http://www.thebody.com/sowadsky/symptoms/symptoms.html). These pictures are a bit too graphic for some people, so be prepared.