I was having a conversation with my wife's father and grandfather about sex drive in older folks. I remember my wife's grandfather saying, "There may be snow on the roof, but there's still plenty of fire in the furnace."
That was his way of saying he still got plenty horny, still got good solid boners. He also had a steady woman he boinked a couple times a week. He was 90 at the time and lived another 7 years.
His "secret" is really no secret at all. "Balance. Balance in everything. Work hard, but relax and have fun, too. Be serious when it's needed, but have plenty of laughs. Eat fruit and veggies, but indulge yourself; have some ice cream, eat a steak. Drink water, but have a few beers every week, too. Friends are important; if you outlive one, make a new one. Exercise can be any physical activity; mow the lawn, weed the flowerbeds. Take a leak outdoors once in a while - it's good for the soul. [He actually pissed outside off his front porch all the time.] Get a good night's sleep; take naps. Have sex, but keep yourself primed, too. (Stokes the air.) All that, and any amount of luck, you'll keep the pilot light lit."
I never got around to asking him what he thought about being naked but, somehow, I imagine he wandered around his house naked when nobody else was there. Chilling in the nude is a great way to relax. When your cock gets hard, the fun can begin.