Ok listen, I'm a white boy who used to have a pancake ass and my jeans and shorts would sag at times, about 3 weeks ago I was told I needed to strengthen my glutes to help my lower back injury so I done some research and saw my options. Started 30 day squat challenge, was told it wont work by "experts" so stopped after the first rest day, looked for the best glute building exercise and saw that deep lunges are supposed to be good. I started off for a couple of days doing X amount of squats with 20 deep WEIGHTED lunges, after another couple of days I cut out the squats because they hurt my back and stuck to plain old deep weighted lunged.
I've been doing 40 about 4 times a week for 2 weeks now and the changes for ME were so quick, I'm talking a matter of days. I put on my jeans which used to sag after a while when I went out with a friend recently, I got compliments from girls and everything. I would even go as far as to say it is one of my best ASSets now lol Seriously though, deep weighted squats, take a picture before on day 1, do it for a week and have a look 7 days later.