to act in a more careful way than you did before, especially by spending less money.
He'll have to draw in his horns, now that he's lost his job.
draw in (one's) horns
To act more cautiously than one did before. I just got this quarter's budget report, and we definitely need to draw in our horns and spend less going forward.
draw (or pull) in your horns
become less assertive or ambitious; draw back.
The image here is of a snail drawing in its retractile tentacles when disturbed.
1991PaulGrescoeFlesh Wound Hollywood's major studios were pulling in their horns in the wake of a disastrous Christmas season.
draw/pull in your ˈhorns
start being more careful in your behaviour, especially by spending less money than before: After making huge losses, the company had to draw in its horns by cancelling some major projects.