Advice for safe sex

[IloveBJ]

Hi guys.

Recently I discovered I am bi and started hanging out with guys.
I always have safe sex. With girls is easy, just put a condom on it and you are well protected.

With guys is different. I am not into anal sex, but I am into oral sex. I like giving oral very much, but don't like sucking condom over the dick.

Can you give me some advice how to have safe oral sex with guys. Is there any way to tell if there is something on someone's penis? Can I see by naked eye if somebody has some STD or it's not possible.

I really don't want to suck dick over a condom.

Thanks in advance.