get off (one's) arse(redirected from get off their arse)
get off (one's) arse
rude slang To start being productive, especially after one has been inactive (and perhaps literally sitting). This phrase is often used as an imperative. Primarily heard in UK, Australia. Get off your arse and help me with this! If you don't get off your arse now, you'll be up all night finishing your paper.