Sexual intercourse, also called coitus, or simply, to have sex is the human form of copulation. In humans this is performed relatively frequently, and primarily for sexual pleasure rather than in response to a seasonal stimulus.
Humans, bonobos and dolphins are all intelligent social animals, whose cooperative behavior proves far more successful than that of any individual alone. In these animals, the use of sex has evolved beyond reproduction to serve additional social functions. Sex reinforces intimate social bonds between individuals to form larger social structures. The resulting cooperation encourages collective tasks that promote the survival of each member of the group.
Among both sexes, the excitement phase results in an increase in heart rate (tachycardia), an increase in breathing rate, and a rise in blood pressure. An hardening of the n_ipples, especially upon direct stimulation, will occur in nearly all females and approximately 60% of males. Vasocongestion of the skin, commonly referred to as the s_ex flush, will occur in approximately 50-75% of females and 25% of males. An increase in muscle tone (myotonia) of certain muscle groups, occurring voluntarily and involuntarily, begins during this phase among both sexes. Also, the external anal sphincter may contract randomly upon contact (or later during orgasm without contact).
Simply put: THE PLEASURE!
2006-12-04 07:48:08
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answer #1
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answered by terryoulboub 5
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