lick your lips idiom
舔嘴唇
to move your tongue along your lips
She took a bite of doughnut and licked her lips. 她咬了一口炸面圈，然后舔了舔嘴唇。
垂涎欲滴地期待
to feel pleasure at the thought of something
He licked his lips at the thought of all that money. 一想到那么多的钱，他就有些迫不及待了。