While many of the comments here are insulting and foolish they do contain a kernel of truth. Being active in any way involves taking on risk. In this area there are not only health risks, but also safety and, possibly, legal. Exposure for anyone with a committed partner. What level of risk are you willing to take on is an appropriate question. Minimizing health risk is a good goal. Hand jobs are clearly the safest. Touching and being touched should be fine. Beyond that, using a condom. Any unprotected activity that involves bodily fluids and the risk of STDs go up. Again, what are you comfortable with?