Perhaps the answer to these questions will vary among men, but all will agree on one thing: there's just something about a nice butt that we find very sexy. When I say "nice," I'm allowing for variations in definition here
Some men like small, perky butts. Some like voluptuous, heart-shaped butts. Some men like firm, athletic butts. Some men like petite, model-like butts. Others like butts that are round, but not obtrusive. Many like shapely butts that are in proportion to a woman's figure
There are some who don't particularly care about butts at all (they are in the minority). Then there are those on the opposite end of the spectrum who like big, even gargantuan butts
Speaking of big butts, they tend to create a more pear-shaped body, which according to scientists makes better use of insulin, which can offer protection against type 2 diabetes and heart disease. In addition, extra "padding" is still believed to facilitate pregnancy