First, masturbate like you normally would. For most men, this would be rubbing/stroking your erect penis. When you feel yourself about to ejaculate, pull the foreskin up over the head completely & hold it shut. The feeling is much more intense than if you just let your cum spill out. Once you're done, release your hold on your penis & let the cum flow onto a tissue, towel, your hand, etc. Wipe up the rest of it from your cock and do whatever you want with it.
You get more pleasure without the mess.