Sex (specifically intercourse) was meant to be moist. If it isn't wet enough, it is, well, uncomfortable. Any discomfort a woman feels is going to slow arousal and make orgasm difficult.
A common misconception is that if you run out of natural lube you are, therefore, not aroused. This myth is widely believed and is -- plain false.
Why is lubricant so important for women to orgasm?
Sex (specifically intercourse) was meant to be moist. If it isn't wet enough, it is, well, uncomfortable. Any discomfort a woman feels is going to slow arousal and make orgasm difficult. Only 30% of women orgasm with intercourse in the wettest of conditions. Add in some distracting discomfort or pain and it is going to be very difficult for any woman to have an orgasm under those conditions.
Discomfort or pain can be killer of sexual arousal and orgasm. A lover could be thrusting away during intercourse. You both are having a grand time and then you start to feel a "roughness", your lips are pulling and it starts to feel uncomfortable. You become aware that you are losing precious natural lube. This is especially true if you are using a condom. Keep in mind that he may not notice as quickly that you are not getting enough lubrication because he literally can't 'feel' as much with a condom.
The mental focus starts to turn to 'lack of wetness' instead of the delicious sexual thought or sensation you were just experiencing. As your focus changes, your body reacts with less arousal and subsequently less lubrication. The anti-lube feedback loop comes into full swing. The more you think of the pain or discomfort, the more your body is not making lubricant, the drier you become. It is this cycle that will kill your arousal and your ability to orgasm.
You could have been the most aroused person in the world a moment before and now you are left dry and becoming drier.
Many women let it go too long for a couple of reasons: a) they are aroused and don't want to stop what they are doing; b) they are worried about hurting their lover's feelings; and c) they are worried about feeling inadequate that they don't lubricate 'enough'.
A common misconception is that if you run out of natural lube you are, therefore, not aroused. This myth is widely believed and is -- plain false. Women lose lubrication for many different reasons that have nothing to do with lack of arousal -- dehydration, age, time in menstrual cycle etc.
What to do if you don't have enough lube with intercourse?
1. Know that you are not alone. This is an issue for most woman at different times.
2. Communicate with your partner. If you don't want to say it, develop a hand gesture signaling a desire to be licked.
3. Drink lots of water a few hours before sex.
4. Stimulate the clitoris. There is no faster way to get a woman's juices flowiwng than clitoral stimulation. Add in some oral sex (lick the vaginal opening) and you have a sure fire way to increase arousal and lubrication.
5. Always have a good lube nearby. Stop what you are doing and grab it. Don't wait for your lover to do it.
If no lube is around, spit on your finger and use saliva. Saliva is a perfectly good lubricant, but often does not last too long. It may be enough to get things going until you get into a positive feedback loop to arousal again.
Lube just makes every sexual act easier and more pleasant.