Sexual arousal (also sexual excitement) is the arousal of sexual desire, during or in anticipation of sexual activity. A number of physiological responses occur in the body and mind as preparation for sexual intercourse and continue during it. Genital responses are not the only changes, but noticeable and necessary for consensual and comfortable intercourse. Male arousal will lead to an erection, and in female arousal the body's response is engorged sexual tissues such as nipples, vulva, clitoris, vaginal walls and vaginal lubrication. Mental stimuli and physical stimuli such as touch, and the internal fluctuation of hormones, can influence sexual arousal.