Most men in our society are not allowed the sight of breasts under the average situation. Anything that society keeps covered general causes a natural curiosity that is often expressed by sexual sensations in the male brain. In some societies of this world, where no male (except for the woman's husband) is allowed to see any part of a woman's body, just the sight of her bar ankle will generally cause a man to have the same sexual feelings that they would here if they saw bare breasts.

Perhaps more important are a woman's curves. Psychological studies have show that men respond sexually to the curvatures of a woman's body and where else are the curves more prominent. Another line of thinking is that a man's desire to suck on a woman's breast allows them to regress to their childhood.