It isn't hard to do; try it anytime you're horny. You don't need a beautiful setting. You needn't say a word. Any time of day will do: a languid morning, a hot afternoon, though I prefer the dark silence of midnight.
Equipment is important, especially for the lazy. Get a quality vibrator. Except when you're camping, of course, or in a country where the current doesn't match, buy one that plugs in; there's nothing worse than a battery giving out at the wrong moment. There are many choices here. My favorite is the Magic Wand, available at any shopping center - large and sturdy, for external use only.
You might prefer the double-duty smaller type (this kind has batteries), but I say, double-duty means compromise. Invest in a proper silicone dildo. The color is up to you. They are all shaped more or less the same, but, as usual, America offers selection. There are smooth dildos. Dildos with pleasure bumps in the French Tickler tradition. There are anatomically correct dildos, bulging veins and all. Be realistic concerning size, especially if you're post-menopausal. Remember, bigger is not necessarily better.
Now you are ready to begin. Lie down. Get comfortable. Music is nice if the vibrator's electricity doesn't interfere with your radio. Fantasize if you wish, but for a quickie, it's not necessary.
Turn on the vibrator. Let it wander around the pillow of your crotch till you find just the right spot. Your body will tell you. Now it's time for the dildo. Give it a good lick up and down its length for lubrication, ease it in all the way. Use your muscles to grasp it, squeeze until your g-spot finds it. You can caress yourself, pinch a nipple, or just sink into your center. It's up to you, only for you. No one will criticize you for being too genitally focused. Stay with it until you feel the earth move.