And the solution to that is to start training the ass to be bigger rather than the far more simple logical solution of buying correct fitting pants in the first place??
Guess if you had pants custom made they would fit any ass, regardless of size or lack there of. Off the rack clothes are designed to fit the average person.
Michael Phelps, Olympic gold medalist has a disproportionately flat ass.
It's been said that women like men with nice muscular asses. Perhaps this is because it is the muscle group most involved when fucking....in other words, thrusting.