Stretching my calves after foam rolling feels amazing. One thing I do is put a weight on my knee after Im in a deep squat to help get my problem ankle flat and stretch things out. But easier than squats would be lunges, split squats, deadlifts, and glute bridges/hip thrusts. These will do a lot for your glutes while you work on your mobility. Going through the motions will help, and its best (highly recommended) to stretch after a workout or warmup (foam rolling gets the blood flowing too).