Presenting - behavior, also known as mammalian lordosis or presenting, is the naturally occurring body posture for sexual receptivity to copulation present in most mammals including rodents, elephants, and cats. . .

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Lordosis behavior is non-functional in humans, although lordosis-like positions can be observed in women being mounted from behind.[11]

In a 2017 study, using 3D models and eye-tracking technology it is shown that the slight thrusting out of a woman's hips influences how attractive others perceive her to be and captures the gaze of both men and women.[12] The authors argue "while reflexive lordosis posture is not exhibited by human females and receptivity is not passive or obligatory for them, a manifestation of lumbar curvature might serve as a vestigial remnant of proceptivity-/receptivity-communicative signal between men and women".[13] Previously, anthropologist Helen Fisher also speculated that when a human female wears high-heeled footwear the buttocks thrusts out and the back arches into a pose that simulates lordosis behavior, which is why high heels are considered "sexy".[14]

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