I masturbate almost daily while writing erotica or reading it. My erections can last for a half-hour while stroking. As I get older, I find my penis needs more lubrication but I haven't found one that is non-greasy and effective. Can any one share their secrets? Several times I've stroked myself "raw" and its quite painful. I read once that silk boxer shorts, or silk anything, helps the stroking without irritating the skin of the shaft.