ok I see guys wearing cock rings around thier balls...why? what is the point? and any dangers? and there are several types of cock rings. some go all the way around like a "ring" and some like a "U" shape sorta and then there of course is the shoe string method. any advantage over one from the others? why so many? and how snuggly should they fit? and should they fit different for different purpopses like if you use it during sex or if you wear it all day long, or whatever other uses there are?