pull your socks up Informal
Meaning: You can say "pull your socks up" to someone if you think they should improve the way they are behaving or the way they are doing something.
- He'll lose his job unless he pulls his socks up and starts doing a lot better.
- The coach said I have to pull my socks up or I'll lose my spot on the team.
His teacher told Jason to pull his socks up because