The wetness you referred to is the secretion of a lubricant from a set of glands that are located on either side of the vulva. Women actually have two kinds of glands called the greater (Bertholin's) and lesser (Skene's) vestibular glands. These differ in size in different women. Skene's glands are the female equivalent of the prostate, while Bertholin's glands are the female equivalent of Cowper's glands. All these glands provide lubrication for intercourse.

What stimulates the activity of these glands is the brain. Foreplay, fantasy, whatever gets you thinking about sex, as well as the physical sensations experienced in foreplay, the anticipation of any kind of sexual activity including bdsm. This is why getting in the mood, however you do it, is so important for the comfort and pleasure especially of the woman during the sexual act.

As lady members have already told us, the amount of lubrication can vary a lot at different times in the menstrual cycle. Women who are sexually inactive early in life sometimes have trouble getting these glands to start working properly. Bertholin's glands can get infected and if they do, afterwards they may not function properly. I think this is relatively rare. Partners who are free from communicable diseases can use saliva as a substitute lubricant. It works well. The use of artificial lubricants can sometimes cause an allergic reaction, in which case the users should change to another type.

Male lubrication works in a very similar way. The transparent lubricant from Cowper's gland can be produced in copious quantities by some men, even during continuous arousal over a period of hours. What many women do not appreciate is that men also need psychological preparation in order to enjoy sex more. Ejaculation can and often does occur without much in the way of sexual gratification, especially if the partner regards the masturbation of a male partner as a purely mechanical process. The buildup to sexual pleasure in the male involves thoughts and sensations, just as it does in a female. It also involves lubrication. It is far more effective to caress around the genitals than grab the obvious part and jerk at it. The feel of woman's touch is so different from their own that in itself it is arousing. Stroking around the scrotum and the lower part of the penis heightens anticipation. It works.

So ladies, take your time. Do everything to get him in the mood, and keep him there. Don't rush it, however desperate he seems. What you are working him up to is an orgasm, and if you get it right, ejaculation ought to occur at about the same time. By itself ejaculation can reduce sexual tension, and even his blood pressure usually drops afterwards, that does not meen that it was the ultimate sexual experience.

To the men, always remember to give your partner the time to get properly lubricated, and tease her mind as well as her body. You do nobody any favours by getting stuck right in.