Boy's mouth waters in anticipation.
Meaning: This means that the boy's mouth is producing saliva because he is excited about eating the cake.
Choice of Words: Boy's indicates that something belongs to a boy. Mouth is the opening in the face through which food is taken in. Waters means to produce saliva in the mouth. In indicates a location or position within something. Anticipation is the feeling of excitement or eagerness before something happens.
Alternative Expressions
Related Expressions