We cannot really control from where we lose and gain fat, its a process that is mainly controlled by genetics. So, its impossible to say when your butt will get bigger (and by how much) when you fatten up.
Otherwise, work your glutes. Here is a large collection of exercises:
karlyndarlin05 answered Sunday February 20 2011, 6:04 pm: Anything fatty, and unhealthy...if you want a bigger butt this way you have to gan weight...a better way of doing it would be to do some exercises like lunges to build up muscle in that area instead. [ karlyndarlin05's advice column | Ask karlyndarlin05 A Question ]
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