When it comes to sexual behavior, people frequently want to know what's "normal". There seems to be a natural tendency to want to compare one's own sexual experience to the average sexual experience, perhaps in an attempt to gauge performance.
Understanding what is happening physiologically during a given sexual experience may or may not enhance the sexual experience; but one thing is for sure, it isn't easy to understand what's "normal" when it comes to sexual response.
Many are familiar with the Masters & Johnson sexual response cycle. This was the original sexual response cycle, published in 1966, based on observations of sexual responsivity during partnered and solo sexual activities. This model of sexual response is still the most commonly taught model, despite its mid-60s debut.
Masters & Johnson found that sexual response was divided into four phases: excitement, plateau, orgasm, and resolution. These four phases happened in a linear way, with one coming after the other. The sexual response cycle wasn't complete without all four occurring (but women had the capability to have multiple orgasms, putting off resolution until all orgasms were complete).
Despite its (even current) wide use, there are some issues that have been identified with this model of sexual response. The model is entirely linear, with one component occuring prior to the next, in the same order. This is problematic because we just don't work that way! The model completely ignores sexual desire and requires an orgasm to have occurred during sexual response (a very unrealistic expectation). Finally, the model is entirely physiological with no mention of relationship factors, cultural attitudes, or any other external contributors that may be crucial when considering sexual response.
In response to these criticisms, other researchers stepped up to try to explain human sexual response. First, Kaplan proposed the Triphasic Concept in 1979 by creating a model that included desire, excitement, and orgasm. However, this was still linear, still required orgasm, and raised the question of whether desire really came before arousal. Then, in 1997, Whipple & Brash-McGreer created the Circular Model that was specific to women. This cycle acknowledged that pleasure and satisfaction during one sexual experience can feed into the initiation of the next sexual experience. If pleasure and satisfaction were not met, it would decrease the desire for subsequent sexual interactions.
Though the Circular Model is an interesting approach, there is a newer model that myself and many other sex researchers and therapists rely on for explaining how sexual response works. This model was proposed by Basson in 2000 as the Non-Linear Model of sexual response. It is typically referred to for explaining women's sexual response, but I think it proves equally useful when looking at men's sexual response. Afterall, too often we think of men as overly-simplistic beings when it comes to sex.
Basson's Non-Linear Model of sexual response incorporates the need for intimacy, acknowledges that desire can be reactive or spontaneous and may come either before or after arousal, recognizes that orgasms may contribute to satisfaction but aren't necessary for satisfaction, and considers relationship factors that may impact the cycle as costs or rewards.
The inability to really define "normal" is one of my favorite aspects of Basson's model. Women (and men) can experience sexual response in a variety of ways. Parts of the model are linear (e.g., arousal and stimulation occur prior to the experience of satisfaction), but other parts are circular and bidirectional (e.g., sexual desire may come before or after arousal and the two may feed into each other).
Three main take-home messages we can learn from studying sexual response cycles:
Try not to focus on "normal". Instead, shift that focus to you and your partner's sexual response and communicate your needs both inside and outside the bedroom.