It's like other musocus membranes: being dehydrated, drinking alcohol, or taking antihistamines can diminish lubrication. Also, according to Sue Johanson, the host of the Canadian program "Talk Sex," once a woman gets to the plateau stage, right before orgasm, she actually stops lubricating, which can be a problem if you practice extended arousal or female orgasm denial.

It has been my experience that the times I'm dripping is when there is no genital stimulation, just anticipation, which supports Spitman's comment that the brain controls lubrication.