fill (one's) head with (something)(redirected from filling their heads with)
fill (one's) head with (something)
To cause one to begin having particular thoughts or ideas. Everything she's said sounds like it's straight out of Pat's wacky schemes. He must be filling her head with crazy ideas.
fill someone's head with something
Fig. to put some kind of ideas into someone's head. Who's been filling your head with ideas like that? Mary has been filling my head with ideas about how to get rich.