This technique works best with a vibrator, but you can give it a try with your fingers as well.
Basically start out masturbating slowly, if using a vibe have it on a low setting and slowly tease yourself until you're ready to cum. As you cum turn the vibrator to max, or rub really fast, spread yourself open all the way with your fingers and put the vibe right on the tip of your clit. Now here's the tricky part, and it will take some will power. Keep the vibe on your clit, after you cum, don't slow it down, don't move it, nothing. I'll be honest with you, it'll be pretty uncomfortable for a minute or two, BUT if you keep it up the uncomfortable stage will end, and right after you'll go into another, MUCH more intense orgasm. I know most of us don't really like our clits touched right after we cum, so this might not sound appealing to some, but if you try it you might find the ultra-intense orgasms to be worth it. I was reluctant to try it as well but my boyfriend convinced me and I'm glad he did.
Happy jacking and jilling ladies and gents.