Beyond all doubt, her naked feet on your naked balls and cock is the best way to go. Besides safety, it's just a whole lot of fun. You get better visual and tactile imagery. However, as we we were recently reminded above, pretty much any of her naked parts on any of your your naked parts are also a lot of fun, and a relatively safer way to go as well.
Aw, hell, screw the safety! My wife's feet are gorgeous, and I want to see and feel all of them. Naked. And on my balls.
poolman2