Use "undercoat" in a sentence

1. Lowering his leg, he stared at it, then urgently parted the coarse outer hairs with a trembling claw, peering closely at the soft undercoat beneath

2. You open your door, the smooth white undercoat of one of the B’s lay outside, tongue hanging from the side of his mouth

3. The trick was to apply three coats, the backing coat or undercoat was electrically conductive and formed one terminal; the next coat was the color layer and reacted to a combination of extremely low voltage and alternating frequency