whet (one's) appetite
To induce or increase one's interest in something. The first chapter of that novel really whetted my appetite—I'm eager to read more of it tonight.
whet one's appetite
Arouse one's interest or eagerness, as in That first Schubert piece whetted my appetite; I hope she sings some others. This idiom, first recorded in 1612, transfers making one hungry for food to other kinds of eagerness.