Let's put our backs into it, lad.
3 seconds sound clip from the Mary Poppins movie soundboard.
You can hear this line at 01:08:19 in the Blu-ray version of the movie.
Quote context
[...]
- Ahoy, there! Ahoy! Good day to you!
- We're going to buy some fish.
- Very good! Proceed at flank speed. Aye aye, sir.
- Let's put our backs into it, lad.
- More spit and polish, that's what's wanted around here.
- Not so fast, please. I can't understand a word you're saying.
[...]