How can I treat a watery vagina during sex,my vagina becomes too watery during sexual intercourse?

You are supposed to become "wet" and slippery with natural lubrication in the vagina during sex. This means that you are stimulated and ready for sex. This is natural and normal. Some women become "wetter" than others but there is nothing you can do to stop this nor should you want to. It is normal natural healthy response and it is to make penetration easier.