go bananas over something
go bananas over (something)
To express great excitement about something in an exuberant manner. She totally went bananas over that wedding dress, so I think it's the one she's ultimately going to pick.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
go bananas over somethingINFORMAL
If you go bananas over something, you become very enthusiastic about it. Everyone went bananas over his new TV show.
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012