Nature
Now I want you to begin fingering your asshole. Go ahead and do it, right now. Lay flat on your stomach, and slip one finger in. Tease yourself for a minute at least, and when you're ready, slip a second finger in. Now, begin to fuck yourself. Grunt, moan, do whatever you want to do. The louder the better. Ha! You sound so great right now, if only I could record it and show it to all of my friends! Oh well, maybe next time.
Now, I want you to slip a third finger in. Getting painful yet? Now fuck yourself like a sissy whore. Set the metronome to 80, and fuck your asshole at that pace for two minutes. Then, continue to fuck yourself in the ass for 3 minutes while you stroked at the same pace as the metronome (keep it at 80).
Close to cumming yet ;)? Well don't! At least not yet.