flat out like a lizard drinking
1. adjective Very busy; preoccupied with many different things at once. Primarily heard in Australia. Sorry I couldn't make it to lunch today, I've been flat out like a lizard drinking all day. I've been flat out like a lizard drinking at work lately—I barely have time to see my kids anymore.
2. adverb At the greatest possible speed, efficiency, or power. Primarily heard in Australia. We drove that car through town flat out like a lizard drinking. The whole team is working flat out like a lizard drinking to get this project finished on time.