sit on (one's) arse(redirected from sit on arse)
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sit on (one's) arse
To be idle, especially when action is needed. Primarily heard in UK. You can't just sit on your arse all summer. Get a job, join a club—do something with your time! I was tired of sitting on my arse while so many people in the city needed help, so I decided to join a homeless shelter and try to lend a hand where I could.