All the lubricants on the market -- even the ones at health food stores -- contain nasty chemicals that you don't want on your skin, much less on sensitive areas like a penis or vagina. So my wife and I recently started using coconut oil (organic extra virgin -- nothing but the best!)
It works great! My wife has a tendency to get yeast infections but hasn't got one since we started using coconut oil -- maybe because coconut oil has anti-fungal properties.
Anyway, that's our experience. Your mileage may vary of course!