Why does my vagina dry out during sexual intercourse?

Friction: It could be related to just the physical act of sex and the friction of the vaginal mucosa that makes you feel dry. This can also lead to the feeling that your vagina is swollen. Another factor could actually be the lubrication you are using. Mineral based lubricants are notorious for making you feel dry. Use water based!

Lack of lubricants: Normally, your vagina produces natural lubricant during sex in response to arousal. This process may be impaired due to a number of possible reasons. The easiest way to deal wiht this problem is to use lubricants designed for this purpose. However, you should also consider other reasons. No infection symptoms? Pain with sex? Psychologically prepared for sexual activity, etc.

Poor arousal: Poor arousal usual is the cause. Need to rule out other less common psychological, emotional or physical problems.