The Missionary position is one of the most popular man-on-top sex position. Althogh nearly all beginners start with this position, the missionary position is still widely practised by many people as it provides a great level of intimacy.
To assume this position, the woman should lie on her back with her legs apart. The man settles between her legs, and one of the two should guide his penis to her vagina. He can support himself on his forearms or simply rest his entire weight upon her, as desired, and she has some freedom regarding where her legs should be; this freedom gives rise to a number of variations in the position, which will be covered further down.
Many couples start with (and return to) the missionary position because it delivers two of the great appeals of sex: full-body contact, and a penis inside a vagina. Additionally, partners are able to kiss, caress, talk and generally exhibit intimate behavior. While the woman does not have much freedom of movement, being constrained by her partner's arms and possibly his weight, this is not necessarily a downside, as women report being unbothered by, or even desiring, the experience of being "taken" in this way. Finally, the missionary position lends itself to a great variety of variations, which can help provide the things it does not lend itself to: intense, athletic sexual stimulation, visual stimulation and freedom of movement for the woman.
The attitude of the woman's legs in relation to herself and her partner are where most of the variety comes from. This gives the woman a bit more control over the proceedings, especially in making sure she gets the penis exactly where she wants it to be.
In general, if the woman raises her legs, her thighs will become increasingly parallel to her torso, allowing the penis to go deeper into her vagina. The general resting places for her legs are:
Deep penetration is typically enjoyable to both sexes, and can allow the man to stimulate his lover's G-spot with his penis when he thrusts. However, it also this increases the possibility of hitting the woman's cervix with his thrusts, which a fair majority of women find uncomfortable or even painful.