Tears, snot and pus...
The human body produces quite a lot of things. And you can encounter some of them during sex.
Pus and snot are full of dangerous bacteria. To prevent them doing
you any harm, don't lick or swallow either of them. As always, the best
way of protecting your dick is a condom.
Don't panic about tears: They too can contain a few hepatitis- and HI-viruses but it would take a river of tears flowing into an open wound to do you any harm.
So put a plaster on any skin wound or scratch, then you don't need
to worry about contact with snot, vomit, earwax, sweat and all the rest.