Sexual arousal in women

There are various stages of physical response during arousal and sex. Researchers have identified four stages of sexual response in women and men: arousal, plateau, orgasm and resolution. This is what happens in a woman's body when sexually aroused.

Stage 1: excitement or arousal

When a woman becomes aroused, the blood vessels in her genitals dilate. There is increased blood flow in the vaginal walls, resulting in fluid passing through them. This is the main source of lubrication, which makes the vagina wet.
Her external genitalia or vulva (including the clitoris, vaginal opening, and inner and outer lips or labia) become engorged (swollen) due to the increased blood supply. Inside her body, the top of the vagina expands.
Her pulse and breathing quicken, and her blood pressure rises. She may become flushed, especially on her chest and neck, due to her blood vessels dilating.

Stage 2: plateau

Blood flow to the lower third of the vagina reaches its limit, and causes the lower area of the vagina to become swollen and firm. This is called the introitus, sometimes known as the orgasmic platform, and it undergoes rhythmic contractions during orgasm.
The woman’s breasts may increase in size by up to 25%, and blood flow to the area around the nipple (the areola) increases, making the nipples look less erect.
As she gets closer to orgasm, her clitoris pulls back against the pubic bone and seems to disappear. A woman needs continuous stimulation in this phase to build up enough sexual excitement for orgasm.

Stage 3: orgasm

Orgasm is the intense and pleasurable release of sexual tension that has built up in the earlier stages, characterised by contractions (0.8 seconds apart) of the genital muscles, including the introitus.

Most women don’t experience the recovery period that men do after an orgasm. A woman may have another orgasm if she's stimulated again.

Not all women have an orgasm every time they have sex. Foreplay is an important role in orgasm occurring in most women. It can include stroking erogenous zones and stimulating the clitoris.

Stage 4: resolution

This is when the woman's body slowly returns to its normal state. Swelling reduces, and breathing and heart rate slow down.

National Health Services - NHS