Noun
kick up the arse (plural kicks up the arse)
(UK, slang, vulgar) A severe reprimand, especially one to motivate someone into doing something.
I need them, need them to give me a kick up the arse. Otherwise I'd just be sat-in getting fat, counting me money. It's good people living on your doorstep and looking through your bins. Gives you energy. Liam Gallagher