Surprisingly, not much research has been done on what a girl can do to alter the makeup of her vaginal secretions in a way that's reflected in the taste, and so most advice for making your vagina taste awesome is based on old wives' tales and anecdotes and hilariously misspelled Yahoo answers. During my informal snooping and asking around, I found pineapple mentioned frequently as vaginal taste aid. Apparently, it's high in sugars, and when you eat it, some internal mechanism sends tiny Magic School Buses to your stomach to cart away the sweet pineapple molecules straight to your vagina. Also recommended: apples, celery, yogurt, red grapes, cranberry juice, lots of water, mint, watermelon, strawberries. Basically, anything that grows that isn't smelly.
According to the anecdata, any food that can make you have weird farts, bad breath, or strong smelling pee should be avoided — beer, coffee, alcohol, asparagus, most dairy, onions, shallots, meat, and fish. And while smoking will make you cool, like cooler than you could ever manage on your own, smoking will make the taste of your body's juices turn sour. If you already smoke and are about to defensively insist that your juices taste like peach nectar, just imagine how scrumptious you'd taste if you kicked the habit.
It should be noted that none of these things (aside from proper personal hygiene) have been beyond-a-shadow-of-a-doubt proven to change your vagina's taste. And if you've got a serious problem with odor or taste, you should consider the fact that there could be an imbalance at play and what you need isn't a pineapple and some oral, but a doctor an some antibiotics.
Finally, if he's got his face buried in your crotch, he's probably not going to be put off if the taste he's experiencing isn't that of a donut or glass of fine whisky; your vagina is never going to taste like a fruit salad, and that's okay. Remember: if he wanted to have a sweet snack, he'd go get a damn smoothie rather than eat your pussy