For Him:

Apply it to knotted, aching shoulders and the cheeks of his bottom before moving down to concentrate on the perineum - the area between his anus and testicles. Let him get used to the feeling before trying it out (on low speed only) on his testicles (cup them in one hand) and the opening of his anus. Depending on what sort of vibrator you have, you might insert it inside his rectum (definitely ask if the idea appeals first, though, and use tons of lubricant) while giving him oral sex or masturbating him with your hands.

For Her:

Again, use it on her shoulders, back, and feet, before moving to the

obvious. Contrary to what the porm industry would have us believe, most women don't insert vibrators, but hold them firmly against the closed labia, sometimes massaging in small circles or using a press-then-lift motion, while applying varying pressure. She knows how she likes it, so it's a good idea to let her show you how it is done. After that, it is a weapon in your hands as you buzz, tease, and take her right to the brink.....then back again (and again).