If you have access to a gym and a smith machine try this...
Oh, a smith machine is just the squat rack where you can twist the bar and lock it in place. Kind of a self spotting feature. What makes it ideal for this is the fact it is on a track.
Its like a normal squat, but your feet should be about a half a step further forward than normal. So you're basically leaning back on the bar. Now do heavy reps. Because of the new alignment, it will work the gluts moreso than a normal squat.