Why do man touch your bum?

We usally check woman for there hotness body, largness of breats, and roundness of bum.We like to feel they firmness and the creek, (the line)we find it hot when having sex with a woman, as it follows to the womans pussy, and tickles the woman which they find lovely and horny and turned on. Its a good trick! it also shows that the woman is yours and not to be messed with.