walk in straight lines

verb1

1. •
   To adhere to a plan, protocol, or train of thought without any deviation or distraction; to stick to the straight and narrow.

   • Macaulay Culkin clean and sober is a good thing. He's walking in straight lines. He's not buckled over in pain and/or withdraws. Dare I say it, has Macaulay turned a new leaf? — 2013