5+ times a day.
Ideally, wash your hands and penis before each treatment (though I never did unless I knew something out of the ordinary had touched them). I’m starting to think the iodine is toxic to any microbacteria that might be present, but I’m not sure.
Concentrate on applying it to the glans and the area directly under the glans (as the skin is the thinnest here), and also at the dorsal base of the penis. I also applied it in the gouch area, between my balls and anus. You should wash that area as you definitely don’t want any dried shit getting in the mixture.