Just wear condom, they really work. Even for oral sex.
Very informative many thanks.
this is a good question...
I would say non specific NGU (trasmitted by oral /anal/ and/or vaginal sex).
Then clamydia. They are common amonst really sexually active people --who have unprotected sex.
Yes, its easier to get it than HIV.
Chlamydia, gonorrhea, herpes are more common than HIV. And syphilis is the least commoon of those three; but still NOT more common than HIV.