Uniting: The Two Become One
Foreplay in all its various forms points beyond itself to the goal of marital intercourse: the sexual union of the spouses. A husband enters his wife, bringing his penis into her vagina. The two become -- in a limited but powerful physical sense, and in an even deeper psychological sense -- "one flesh," as the Hebrew Bible described it.
Today it is common to think of sex simply in terms of the pleasurable sensations each partner helps the other to achieve. That is why so many people -- not only secular people, but also a large majority of Protestant Christians -- think that there is no great difference between sexual intercourse and various forms of mutual masturbation (in which the partners stimulate each other to orgasm, without actual sexual union).
But, as I have already maintained elsewhere on this website, the very goal of sex is personal union with one's beloved. This means the sex is something that you don't do "to" each other, but something you do together -- which is achieved best by joining yourselves to one another. This begins with foreplay (kissing, body-to-body contact, glossing), but achieves greater depth and power in the joining of the two bodies, by the insertion of the penis into the vagina.
It is not surprising, then, that vaginal intercourse is uniquely satisfying to many women. (The work of researcher Stuart Brody on this subject is particularly interesting.) This is not a question of what gives a more intense sexual response (physiologically). Direct clitoral stimulation does that best, and that doesn't require vaginal intercourse (though a knowledge of feminine physiology makes it clear that the clitoris is not "left out" in penile-vaginal intercourse). But the issue is not one of the intensity of the physiological reaction so much as the sexual "satisfaction," a much broader concept. This explains one fact that often puzzles men: namely, that women can "have sex" and not achieve orgasm and yet find it enjoyable and fulfilling. (This is not to advocate indifference to a woman's orgasm -- I don't understand how any man can be indifferent to that! -- it's just to state a fact, and one with significant implications for understanding marital sexual relations.)
The Forms of Union
A great deal of attention in "sex manuals," from the Kama Sutra to The Joy of Sex, is devoted to sex positions. In a website devoted to reflection on the meaning of sex -- especially its personal dimension -- there's not much reason to get into the question of various positions. Variety in marital lovemaking is, like variety in other matters of sense pleasure (eating meals, for example) normal and appropriate. Hardly anyone would like to make love the exact same way every time. (As I mention elsewhere, I think that marital couples often find a lovemaking pattern they particularly like, and follow that for a while, and then modify it, or try something new eventually, and do that for a while, and then evolve to something else.)
There are some strengths and weaknesses of different sex positions. One reason for the clear popularity of the so-called missionary position is that it enhances the personal intimacy of the act, by allowing the spouses to look at each other more easily. Contrariwise, the so-called doggy position makes it more difficult to do that. But these factors are of limited importance, especially when couples can use various positions both within a given act and across their marital life.
But what has to be said is that an excessive focus on positions and on variety and ever-new ways of achieving sexual pleasure detracts from the focus on the person that should be at the heart of married intimacy.
When a man makes love to his wife, the key is that he seek sexual union, which involves physical union, but also emotional and personal union (a union of souls) as well. Marital lovemaking that doesn't bring physical pleasure and delight to both husband and wife is not living up to what it should be. But ordinarily a husband and wife who love each other will not have difficulty achieving that pleasure. And it is worth noting that a one-sided focus on physical pleasure can boomerang, can undermine that pleasure (higher expectations, in the normal course of human life, won't always be achieved; and a one-sided focus on physical pleasure by one partner can also undermine the other partner's sense that this act is about her, not just his feeling good) . Achieving a more complete personal union -- especially given the emotional differences between man and woman -- can be a challenge.
Probably the most important thing to say is that, as long as a man enters with his penis into his wife's vagina and ejaculates in her, sexual union has been accomplished, and the details of the method are secondary. (For more on rights and wrongs in married sex, see here.)
The Action in Union
As is so often the case in sexual matters, there is not just "one way" to do something. (Is there just one way to "kiss"? Obviously not!) When the couple are physically connected through the union of penis and vagina, they can move and act in various ways.
The initial entry is often a very wonderful moment, since it is often powerful for the wife -- eliciting a shudder or moan -- in a way that makes it very powerful for her husband as well. Of course, as in all aspects of the marital act, the husband should be sensitive to how his wife feels, how she likes to be entered. A good general rule is to enter fairly slowly, which also helps build up anticipation. (One of the more sensible, practical sides of the Kama Sutra is the recognition that the genitals of a man and a woman vary in size, and the relationship of the sizes in a couple has an impact on their marital lovemaking. Whatever the relation, each spouse must be sensitive to the capacities and needs of the other. Men, in particular, have to have a sensitive care in uniting with their spouses.)
Once a man has entered his wife, there are many ways to move. Sometimes, just moving around very slowly, or perhaps entering deeply and simply holding it there briefly, can give great pleasure. As always, a focus on her, and communicating love, tenderness, and passion are what should guide a man.
But one of the most natural and key elements of sexual intercourse is certainly thrusting, since the movement back and forth in the vagina stimulates both husband and wife and helps to create a rhythm between them. It also is a manifestation of the man coming to, pursuing, acting on, and giving to his beloved, and of the wife receiving, and responding to, the action of her husband. (That response may sometimes, especially as orgasm approaches, be corresponding thrusts of her own.)
The form of thrusting can vary: shallow or deep (which may affect the pleasure of both husband and wife, in different ways), at various angles, with various speeds. It can follow a pattern that is consistent or shifting. The thrusting can sometimes be slow, at other times somewhat faster, and sometimes very fast (though a man ought to be careful about assuming that faster is better -- that is not always the case, at all). It is probably more common to start with slow thrusting and to move eventually to faster thrusting, but the pace can be varied.
I'm aware that there are ways to have marital intercourse that don't involve thrusting -- the coital alignment technique is the most obvious one -- and I'm not saying that thrusting is necessary. It just seems to be the most typical way of having marital relations, and thrusting is, as I said above, somewhat a reflection of the general role of male and female in marital lovemaking, despite the great variety of forms that marital lovemaking may take.
But the most important rule is simply to observe what your beloved responds to, what she likes. That may not be the same every time. So just paying attention, experimenting a bit, seeing what she likes is the most sensible path to take.