Set up: Seated on a fitball or chair, feet in front of your knees. Spine should be in neutral with shoulders back and down.
Keep upright but relaxed, let go through abdominals and pelvic floor. Tighten back passage, then front passage. Lift through pelvic floor and hold whilst you continue to breathe normally. Release and repeat. Make sure you are breathing into your sides (avoid chest and belly breathing) and keep your body relaxed, avoid tensing through legs, glutes and torso.