When you take a sip of your drink, it engages your lips so it draws attention to them, but at the same time, if you look away it has the added benefit of giving him a moment to look at you, and take you in without you staring right back at him.
當你在喝飲料的時候,這個動作包含了你的嘴唇,這會吸引他的注意力,同時如果你在這時候看向其他地方,這就正好給了他一個看你的機會,也避免了四目交接的尷尬。