Sit on the floor with your elbows resting on a bench, chair, or couch behind you and a booty band around the bottom of your thighs. Make sure you're seated tall, lengthening through your spine. Do not slouch. (Optional: hold your pet securely!)
Open your knees to either side, pushing against the booty band for resistance as you do.
Go as far as your hips allow without causing pain, then bring your knees back together. This counts as one rep.