This will randomly select an idiom and will explain it to you.
Ask the Professor to tell you about any idioms with a certain word or words in them. The Professor will go through them one by one, and if you find the one you were looking for, he will give explain it to you.
You could also be very specific. Just ask the Professor to explain a particular idiom that you are interested in.
You can also say:
"Alexa, ask the English Professor what does it mean to spill the beans.
We have English Professors from Canada, the United States of America, England, Australia, and India.