If he's having trouble getting a firm erection, rub a small amount of oil or lubricant onto your palms and put one hand firmly around the base of his penis. Work the other hand from the base up to the head in a circular, twisting motion, as if you were following a winding staircase up his appendage. Caress the head with your palm. Then start at the bottom again. This staircase goes only one way: up.