go potty

verb2

1. •
   To go and use the potty: to leave in order to urinate or defecate.

   • I have to go potty!
2. •
   (UK) To go crazy: to become insane.

   • 'That was the worst thing,' says Adrian. 'My mother just went potty. She said he was going to rot in hell for that. — 2008