on a high
1. In a state of euphoric happiness. We were all on a high after our dramatic win over our cross-town rivals. Jake's been on a high ever since he found out he was accepted to his top school.
2. At a successful, impressive, or climactic point. After winning the Oscar, he decided to retire from acting on a high. I know we've had quite a few losses this season, but let's win this last game and go out on a high!
on a high
in a state of euphoria. informal This expression was originally mid 20th-century US slang, referring specifically to the euphoria induced by drugs.