The kids were salivating when they saw the table full of desserts.

salivating 是动词 salivate 的现在分词形式。salivate 由拉丁词根 saliv-（唾液）和动词后缀 -ate 组成，字面意思是"分泌唾液"。在这里引申为"因兴奋或期待而流口水"的动作。