My husband and I have been together for 6 years, and I frequently give oral sex and therefore know quite well what his penis looks like. Yesterday I began the act and right off the bat noticed a distinct purplish black ring around his penis. It is about an inch below the head and circles all the way around. What in the world would this be? I am oncerned he may be cheating and has caught something which scares the heck out of me for my own health. Please help if you have ever heard of such a marking or experienced it yourself. Thank you so much. (Oh by the way, I immediately asked him what it was and he acted like he didnt know what I was talking about, hen got up and looked in mirror, then said he asked his dr about it and they told him it was normal discoloratrion. Well I am sorry but if he "didnt know what I was talking about" then he never would have been talking to his dr about it and also it wasnt there the last time I did oral sex which was just a few weeks prior.)