This is a little complicated, so I broke it down into steps:
1) Take a great big, thick cucumber and cut one end off of it.
2) Using a soup spoon, carefully hollow it out, but make sure and leave a pretty thick wall (3/8' thick or more)
3) Near the end you didn't cut off, punch a small hole with a pencil into the chamber you created with the spoon.
4) Microwave the cucumber for about 8 to 10 seconds on high.
5) Check with your finger to make sure the insides aren't dangerously hot.
6) Pour a little vegetable oil into the cucumber.
You're now ready to do the fun stuff.
Stick your penis into the cucumber as far as it will go, and then hold your thumb over the hole you made with the pencil when you pull your penis out. It's like a vagina with suction!