Sore butt

So I am not sure if it was the five spins classes this past week or those crazy squats and lunges on the exercise ball. Or maybe a combo of the two. But my glutes are sore.
This is a good thing. I need the most work on my butt, hips and thighs. So I am thinking of getting an exercise ball to use at home. I can watch TV while “Williams sistering” my butt and thighs. (I do have some Target gift cards I haven’t used yet–exercise ball would be a good purchase.)