Donkey work is work which is hard, repetitive and boring.
I am tired of doing the donkey work while my workmates get all the fun and creative tasks.
If you want a promotion, you have to do a lot of donkey work first.
Donkey's years is an expression which means 'a long time'. It's used informally.
I've been living in this house for donkey's years.
Taking a 'donkey ride' at the seaside is a popular activity in Britain. But it can be hard work for donkeys. A set of guidelines by The Donkey Sanctuary and the British Equine Veterinary Association says donkeys shouldn't carry people heavier than 50 kg; they must have at least one day off a week and an hour's rest at lunchtime or early evening.