There has been a lot of debate and talk about hydration, caffeine, ginseng, and sex. It is true that magnesium is the missing building block of life and can lead to more sexual stamina. Not an instant effect, like just taking a stimulant and going off, which may not really lead to an orgasm, but a missing link in the bodies' health. The Egyptian culture has much, much less cancer then us in the Western world. Some say that it is because we are lacking in magnesium. Upon first use, magnesium can have kind of a "heat pad" affect; it can help with knots and tension like potassium.
Hydration for sex will not help sensitivity, or sensation. However, when you first wake up, one thing that we have learned is even if it only takes you one minute, drink two glasses of water quickly. It gets all the vital organs working correctly. In the army and in the desert, it is why GI's are forced to slam bottles of water. It's not just how much they sweat out, it's keeping the organs functioning since we are composed of about 60 percent water.
Having a father who is a general practitioner, I have always known that the urine stream should be white after being awake for awhile. There are conflicting views, but it is known that coffee dehydrates. As far as dealing with sex, what should be known is that if you are well hydrated, then you do a aperture of cappuccino or a regular coffee, if you have a naked babe in front of you, you may react rather well, the heart rate rises, there the dick, just like your brain, starts thinking about a nice warm place to be. Even though coffee is said to be a diuretic, once hydrated, you can use it in strong little shots to get you in the mood for sex.
One scenario we need to look at even though it involved alcohol is the morning during a hangover. Your head is not pounding, however, your consumption the night before has made it so that you really feel your blood pressure doing strange things while you have sex and get rid of the initial booze sweat. Even though we know it will make you urinate again soon, drink two glasses of water before this type of hungover meeting. It will almost automatically get the blood pressure back to normal, and help your overall function.
As far as nutrients, strange herbs, and the like, ginseng should be brought up when dealing with sexual matters. In the orient especially during the 1950's, ginseng was given in pill form as a sexual stimulant. It's not entirely full of beneficial minerals, and I hate to compare it to ephedrine, but it's kind of got the same puritanical buzz, cold, clear, and placid. Another thing about Ginseng is that it Promotes alertness and clarity of thought. When using ginseng it can upset your stomach just a bit. You can combat it with a shot of pepto bismol or ginger pill. I myself have taken ginseng root, a bit of wine, and absolutely noticed a difference in the cold, lovely realities of having sex then if just doing it without. For me I did not continue using it because of the stomach problems, but they are mild, and not acidic, just a bit upsetting. Overall we would advise for healthy sexual activity, the water and magnesium are probably the safest route.
There are many conflicting views on water and sex but what has been absolutely proven is that having sex while dehydrated will be pleasurable at first, however will end in sheer dizziness. The best way to drink water is quickly, if its not your favorite beverage, add some cucumber or lemon. Bottoms up! And hopefully your partner has their bottom up, or legs spread as well, ready for your hydrated body.