Phil Robertson might disagree. The issue is swapping blood, and fluids. Certainly, the receiving party is at much greater risk, but still. I suspect STDs are gonna be a problem for ISIS veterans far into the future.
Obviously, both parties have hygiene issues with such a practice. However, the receiving party has a much, much higher possibility of exposing their circulatory system to potential infection than the giving party (unless he has open wounds on his penis). The possibility of female to male transmission (even with this high-risk practice) is very low. In all likelihood, the ISIS boys got this infection from their buddies or a needle.