Apply tea Yi Xuan to your lips, and press your upper lip with your forefinger and thumb.
With your forefinger still, gently massage your upper lip with your thumb; Pinch your lower lip with your forefinger and thumb.
Without moving your thumb, gently move your index finger to massage your lower lip. Then, massage the upper and lower lips rhythmically in the opposite direction and repeat it several times.
Stick to it for a while and your lips will naturally plump.