The sexual response usually goes through three phases: excitement, climax and resolution. These three phases may not run in parallel on both partners – in fact, usually each partner goes through them in his/her own pace, and this pace varies from day to day and from situation to situation.
The sexual response is a natural one, as many others. If we allow sex to happen naturally, our bodies will respond without any conscious effort on our part. On the other hand, the occurrence of disturbing factors may disrupt the sexual response. These disturbing factors may be of several kinds. They may be related to lack of information. One may not know what to expect (or have unrealistic expectations), or one may not know the partner's sexual preferences and the «techniques» that would allow the couple to «function well» sexually.
These disturbing factors may also be related to psychological factors, in one or both partners. These may be upsetting emotions or disturbing thoughts about the self, the partner, or about sex itself. Or these disturbing factors may be related to other in the couple`s relationship.
Often, the initial factors have already been overcome, but the problems persist. This is because, having «failed» before, the person develops the fear of «failing» again, and this fear itself inhibits or disrupts the sexual response.