make (one's) mouth water
1. To cause one to salivate or feel hungry. Just the thought of having a big seafood dinner tonight makes my mouth water. The smell of the burgers on the grill made Jake's mouth water.
2. By extension, to cause one to feel happy or excited, usually with anticipation. A business opportunity like that is enough to make anyone's mouth water!
make somebody’s ˈmouth water
make somebody feel hungry; make somebody want to do or have something very much: The smell of your cooking is making my mouth water.The sight of all that money made his mouth water. ▶ ˈmouth-watering adj.: a mouth-watering smell