If you want to keep up with Iggy Azalea, you've got to surrender to the mother of all butt exercises: the squat. Begin by standing with your feet side by side, a shoulder's width apart. Then, lower your hips as if you're about to sit on a chair, keeping your knees over your toes. Form is key, which means your torso and back must be kept straight at all times. Repeat and do that, do that.
First step: Imagine Nicki Minaj as your personal trainer. Next, stand facing a chair with your feet hip's width apart with hands on your hips. Step up onto the seat with one foot and lift your body up, then swing your bent left knee to hip height. Hinge forward, then kick your left leg back straightening it as high as you can. Complete the kickback by stepping off the chair with your left foot, then your right. Repeat, or else.