Im not a doctor nor do i do this. People with certain health problems can cause real problems, i know nothing about those diseases listed online, for pumping shaft or balls. Long term affects we really dont know, going to extremes like rayay does is warned against, doing it to often, to much etc. you can research it, a lot out there is about pumping shaft. I doubt many doctors research this thats why we truly dont know what could happen exactly. Pumping either or was listed as a form of treatment for ED. Looked it up, diseases affecting blood, people shouldnt pump because it increases the risk of complications.