whet somebody's appetite

ˌwhet somebody’s ˈappetite

make somebody feel hungry; make somebody interested in something: Don’t eat too much of this dish. It’s only to whet your appetite for the main course.One of my teachers lent me a book about climbing, and it really whetted my appetite.
If you whet a knife, sword, etc., you make it sharper.
See also: appetite, whet