Teak Sealer

[sailsmanship]

Have a teak transom rail that was badly weathered. I sanded it completely and it looks good. I have oiled it and the color looks look but I would like it to stay shiny. I am confused though. My neighbor says he uses teak sealer over oil to make it last longer, but when I look at cans of this it says must be free of oil and dirt before applying. Is a sealer really a varnish that is supposed to be used on bare wood? I guess what I really would like to know is there a product to go over the oil to slow down the drying out process so I don't have to oil so often?