Ok - try to give her oral, but do it so that you are in the 69 position with her underneath and you on top! Make sure that your manhood is in close reach of her and, who knows, she may get the hint!

Or you could try coating your manhood with yogurt/chocolate etc. and see if she'll suck that off - won't work if shes on a diet, though!

Or the best advice - sit down and talk to her, tell her what you want and how much it would mean to you...
and if that fails, well - thats what wine is for