KY jelly is for sex with a woman because it is water-based and will not irritate a woman, vasoline is for wacking. When I did my 14 times in one day, at about the age of 33, I was using vasoline and suffered no bad effects, except for a complete loss of interest in sex for a couple of days. After about 5 times it was not much fun any more, and after 10 times it became a tedius chore, and the porn was boring.