God is the one who invented sex, and He obviously created it for pleasure as well as for procreation. The Bible, however, plainly states that sexual relations are only to be enjoyed by those who have joined themselves together in a life-long marriage covenant.
Sexual relations that take place outside the bonds of marriage are classified as either fornication or adultery. The apostle Paul stated that those who practice such things will not inherit the kingdom of God (see 1 Cor. 6:9-11). Although a Christian might be tempted and might possibly fall into an act of fornication or adultery, he will feel great condemnation in his spirit that will lead him to repentance.
Paul also gave some specific instruction regarding the sexual responsibilities of husbands and wives:
But because of immoralities, let each man have his own wife, and let each woman have her own husband. Let the husband fulfill his duty to his wife, and likewise also the wife to her husband. The wife does not have authority over her own body, but the husband does; and likewise also the husband does not have authority over his own body, but the wife does. Stop depriving one another, except by agreement for a time that you may devote yourselves to prayer, and come together again lest Satan tempt you because of your lack of self-control (1 Cor. 7:2-5).
These verses make it very plain that sex should not be used as a “reward” by either husband or wife because neither has authority over his own body.
Moreover, sex is a God-given gift and not unholy or sinful as long as it stays within the confines of marriage. Paul encouraged married Christian couples to engage in sexual relations. Furthermore, we find this advice to Christian husbands in the book of Proverbs:
Let your fountain be blessed, and rejoice in the wife of your youth. As a loving hind and a graceful doe, let her breasts satisfy you at all times; be exhilarated always with her love (Prov. 5:18-19).
If Christian couples are to enjoy a mutually satisfying sexual relationship, husbands and wives should understand that there is a vast difference between the sexual nature of men and women. By comparison, a man’s sexual nature is more physical, whereas a woman’s sexual nature is connected with her emotions. Men become sexually excited by visual stimulation (see Matt. 5:28), whereas women tend to be sexually excited by relationships and by touch (see 1 Cor. 7:1). Men are sexually attracted to women who appeal to their eyes; whereas women tend to be sexually attracted to men they admire for more reasons than just physical attractiveness. Thus wise wives look their best to please their husbands all the time. And wise husbands show their affection for their wives all day long by hugs and thoughtful acts of kindness, rather than expecting their wives to be “turned on” in an instant at the end of the day.
A man’s degree of sexual desire tends to increase with the build-up of semen in his body, whereas a woman’s sexual desire increases or decreases depending upon her menstrual cycle. Men have the capacity to be sexually excited and experience sexual climax within a matter of seconds or minutes; women take much longer. Although he is normally physically ready for actual intercourse in seconds, her body may not be physically ready for as much as half an hour. Thus wise husbands take their time in sexual foreplay with caresses, kisses and manual stimulation of those areas of her body that will result in her becoming ready for intercourse. If he doesn’t know where those parts of her body are, he should ask her. Additionally, He should know that although he has the capacity for reaching only one sexual climax, his wife has the capacity for more. He should see that she receives what she desires.
It is vital for Christian husbands and wives to discuss their needs honestly with one another and learn as much as they can about how the opposite sex differs. Through months and years of communication, discovery and practice, sexual relationships between husbands and wives can result in ever-increasing blessedness.
 For more proof that God is not prudish, see Song of Solomon 7:1-9 and Leviticus 18:1-23.