Back at school we'd have brass instrument lessons as a group of three, me on french horn, a pal on tenor horn (a brass band instrument) and another on trombone. After one rather poor showing our dryly sarcastic teacher said "time's up. I need my coffee break ... though after you three I need a whisky break!"
Anyhow, hope this helps as an alternative to coffee
Regarding our teacher, I thought he was great, but others did find him a bit much.
