When you insert your thumb, index, and middle fingers into someone's anus or vagina in the shape of a bird beak. With your fingers inserted you open and close the beak while making a crowing sound.
A parable passed down for generations describing the futility of the unintelligent to perform simple tasks.
Since ancient times, when an imbecile, ill-advised coworker or friend has attempted an assignment beyond their capabilities, they are often compared to a monkey endlessly trying to fix an engine that won't start by beating on it with a hammer, because monkeys do not possess the skills of a mechanic.
After being shown how twice, Dan never did learn how to open the fence, so it rained on him a few hours later. He was just like a Monkey Beating An Engine With A Hammer that day.