cock cleaning

Just wondering what’s everyone’s opinions on cleaning your anas or penis as well as cleaning your friends penis to prevent transferable infections for both parties? My biggest fear is getting my best friend sick or my self getting seriously ill from an infection or disease.

What are some tips on keeping a male dog's sheath & cock clean in ways that are agreeable to them? I know they generally keep themselves clean, but I'm new to all this & have yet to gain any "acquired tastes", if you know what I mean...