Try my Dribbler method. It's not a matter of coming, as far as an orgasm is concerned, but it is possible, with practice, to use self control so as to ejaculate without the force of orgasm, so it only dribbles out & then stop for a minute or two. This mean that without having hit the orgasm you remain hard & able to continue the session through multiple ejaculations. It also seems to have the effect that each non-orgasmic ejaculation you manage to achieve stores up the sensation of each orgasm it missed out on until you can't hold it any longer & explode in an ultimate orgasm so powerful that you feel like you're going to pass out. The best I've ever managed is 10 ejaculations, but from the power of the resultant orgasm that that provided, I'm not sure I could have survived any more.