The fine art of anus-shaving
Ah butt shaving,
The easiest route would be to simply approach some gay people standing around a cafe somewhere and ask while holding in your hands some shaving gel and razors: "Hey, lets shave my anus hairs, what do you say!?" You'd be surprised how helpful they may be to you.
But if that's not your thing, well here is a link:
Body shaving guide
"Between your genitals and anus is an area you shouldn’t miss. Once you’re shaved, you’re more likely to receive visitors down there. When shaving around the anus, stretch the skin of each cheek away from the orifice to get a good pass with the blade. If you are shaving yourself, squat in the tub. Razor bumps should be prevented here, so starting the day after your shave, exfoliate with a washcloth in the shower. Keep this area shaved to avoid uncomfortable stubble. Never press the razor hard against the skin here!
By the way, if you have perfected the martial art of silent farts, the lack of hair around the anus will make it impossible to fart silently from now on. Change your diet or something!"