Okay I saw this post and had a laugh, not at anyone trying to increase bum size but because mine is very large lol. I have a bubble butt to say the least. And well to tell you the truth, I'm not exactly sure what made me have one, growing up I never had one, barely had one in my preteens, but by the time I was 14 boom, I had a round booty, and after having a child, my hips widened and butt got even bigger!!! Now one thing I can say is... I use to put salt in my hand and lick it off, gross I know, but I loved the taste of salt growing up, and as I was doing it my mom told me, you keep doing that and you're going to end up with a big butt, well guess she was right! LOL but other than this, I don't know if any of the girls here know about this but I do butt squeezes. When I was 12 all the other girls were getting butts and boobs, I was flat, and I asked a girl with a really nice bubble butt what her secret was and she showed me these butt squeezes that she did everyday, every morning and every night. I started doing them, and like I said after a while, I had a butt, so it must have done something. The best way I can describe to do this is... you lay on the bed or stand up, flex your butt really tight, kind of like stretching in the morning while on your tummy. Hold the flex of your butt for a few seconds, release and do it again, you just keep doing that for however long you want. I use to do it till I was sore! Also I agree that lunges and squats really help, your butt is a big muscle, if you work that muscle it will increase. I'm gonna upload a pic of my butt here, sorry if it offends anyone, but I'm just not shy lol.
My butt measures about 38 to 39 inches, my hips are 36 to 37 currently 37. My waist is 26. The first pic is most recent, the second pic is from early last year, and the last pic is from about 2 years ago.