Famed sex researchers William H. Masters and Virginia E. Johnson were the first to identify the human sexual response cycle. The cycle consists of four phases: excitement, plateau, orgasm, and resolution. But full sexual response is not limited to intercourse, as there are many similar things that happen to your body during oral sex, masturbation, and fantasy as what occurs during vaginal intercourse.

Oral sex, especially, is an important part of many relationships. Oral can range from an act of foreplay to the main event. Couples whose sexual relationship is exclusively oral will tell you that they most definitely experience the four phases of sexual response as well as all of the body changes related to sexually stimulating activities.

It's important to recognize the way your body responds and changes to sexual arousal. The experts at the University of California, Santa Barbara agree that knowledge and understanding of the changes that your body undergoes during a sexual encounter can help "enhance your sexual experiences, deepen your relationship with a partner, or resolve the origins of a sexual problem."

You may have been too distracted to notice the ways in which your body physically responds to receiving oral sex, but if keep your eyes and senses alert next time, you may just notice some of these things happening to you.

1. Lubrication Increases


A woman's first sign of sexual arousal is the appearance of vaginal lubrication. According to Daily Mail, vaginal lubrication starts to be secreted around 10 to 30 seconds after stimulation and the amount of fluid increases as excitement builds.

2. Nipples Become Erect


According to Columbia University, the skin of the nipple is full of sensitive nerves that when stimulated, send a message to the smooth muscle in that area to contract. When the muscle contracts, the nipple gets tighter, and produces a nipple erection.

3. Breast Get Bigger


When a woman is aroused, her breast can actually increase in size due to increased blood flow. The Daily Mail reports that a woman's breasts can temporarily enlarge 20 to 25 percent during sex.

4. Labia Swells And Separates


Vasocongestion, which is the increased blood flow to the genitals, causes the labia to swell during sexual activity, according the University of California, Santa Barbara. The labia also separates in preparation for intercourse.

5. Clitoris Retracts


University of California, Santa Barbara also reports that because the clitoris becomes highly sensitive, it will retract under the clitoral hood to avoid direct stimulation or contact.

6. Skin Blotches


Health educator Deb Levine told WebMD that a "sex flush" may appear on the stomach, chest, shoulders, neck or face when a woman is being sexually stimulated. The skin may redden or appear blotchy.

7. Heart Rate Increases


In the throws of passion, your heart rate, blood pressure and breathing rate will all increase, according to University of California, Santa Barbara.

8. Involuntary Muscle Contractions


During the climax phase of oral sex, WebMD explained that muscles in the thighs, hips, hands and buttocks tense, and spasms may begin. The first third of the vaginal walls contract rhythmically approximately every eight-tenths of a second, and the uterine muscles will also contract.

9. Body Releases Endorphins


Upon orgasm, the body will release endorphins. It will then begin to return to original state. Body parts will return to their normal size, and there will often be a general sense of well-being, intimacy, and fatigue according to the University of California, Santa Barbara.