What's he mean by "count sheep?"
Native speaker’s answer
Rebecca
By "count sheep," he's referring to a method of getting to sleep! The method is when you imagine sheep jumping over a fence as you count them! The counting is supposed to make you sleepy. This is said to come from the time of medieval Britain when shepherds had to do a headcount of their sheep to make sure they were all in the herd. The shepherds would do it before they slept! Ex: Did you try counting sheep? Ex: I couldn't fall asleep last night, so I counted sheep. But that didn't work either. Ex: Before I get to 100 sheep, I always fall asleep.