Did you see the look in his eyes? I smell a rat.
Stop! I'm sure I closed the door before going out. And now it's open. I smell a rat.

I heard straight from the horse's mouth that our boss resigned this morning.
We have a test tomorrow. -- Where did you hear that? -- It came straight from the horse's mouth. Our teacher told me.

He's betting on the wrong horse if he thinks that by flattering the CEO's assistant he'll get a better job.
I'm afraid you are betting on the wrong horse by putting all your money into their stocks.

Why don't you take the bull by the horns and tell him to leave immediately?
I took the bull by the horns and confronted him about his drinking.

I was like a bull in a china shop as a child. I never knew how to talk to girls.
You storm in here like a bull in a china shop and expect us to stay calm?

The producer hit the bull's eye with the film music too.
He threw the spear and hit the bull's eye.

We can talk until the cows come home this weekend at my place.
I can explain this to you until the cows come home but you're just never going to get it.

Steve came home late last night and his wife found a lipstick mark on his collar. He is definitely in the dog house now.
Sorry, I need to get going. I promised my wife that I would come before five and help her with the shopping. I want to stay out of the dog house you know.

Their son never leaves home if it's not necessary. All he does is read, read and read. He is such a bookworm.
She was wearing a very strange dress and bookworm glasses.

Come on, it's not such a big deal. Don't make a mountain out of a molehill.
You're making a mountain out of a molehill now. If he can't pay you back this month, I'm sure he will do it next month.

Cut out the monkey business at once, Steve!
Focus. There's no time for monkey business.

Well, you will have to break your piggy bank, Tommy, if you want that ball.
You want to spend all the money now? Why don't you put it in your piggy bank?

Kevin wrapped himself in a blanket in front of the TV, soothing his cold turkey by watching his favourite shows.
The house price collapse of the last few years has been a terrible dose of cold turkey for some real estate owners.

Circumstances which made someone, perhaps fifty years ago, considered to be the black sheep of the family, aren't necessarily the same now.
The term is used negatively, but the black sheep of the family may be an attractive person, someone with courage to be different.

And her disappearing for a week was the straw that broke the camel's back. He filed for divorce.
When his daughter refused to go to bed past after midnight, he started shouting at her like a mad man. It was the last straw (that broke the camel's back).