Your question brings up the popular topic of teens (as well as adults) wanting to know if the types of activities they derive sexual pleasure from are normal. People are unique, and there are many ways to express affection and enjoy physical satisfaction.
This said, it is not medically safe to engage in this type of "piss sex". Urinating on someone"s face can cause irritation to the eyes, nose, mouth, and skin. Urine can be acidic, as well as contain bacteria that can be harmful if it comes in contact with mucous membranes (like the eyes).
As with any sex act, this discussion would not be complete if FX did not say something about safer sex. FX always recommends practicing safer sex by using lubricated latex condoms, dental dams, or another barrier method.
If you live in the northern NJ area and would like to make an appointment with a physician for STD screening and additional information on how to stay healthy, you can call the Adolescent/Young Adult Center for Health at (973) 971-6475, or your local teen health center or Planned Parenthood.