Lie on your back with your hands on the floor by your sides. Bend your knees and place your feet flat on the floor, then lift your hips up into a glute bridge.
Slowly lower your hips to tap the floor, then press back up into a bridge, trying to keep your hips even the whole time. That's one rep.
Aim for 20 reps total, squeezing at the top to activate the glutes.