This technique might sound a bit gross but don't hate on it until you've tried it.
First, you have to have at least one banana, but it works better with two. Especially if you have a thick dick. You peel the bananas and throw away the inside (or eat if, if you can't bare to waste) and keep the peels.
Sometimes I will put them in the microwave for a quick time, just to warm up. You then place the peel/s on either side of your dick. You can hold them in place with an elastic if you would like. You then proceed to jerk off - the inside of the peel provides great lubrication and ends off with an amazing orgasm.
To intensify any orgasm, a hint I have heard of but not tried yet, is to keep a tub of ice close by. Keep the ice touching your butthole throughout, this apparently offers a greater orgasm.