"let the cat out of the bag"
Which means to tell a secret or spoil a surprise?
"it's not my cup of tea"
It's not something I like
"slipped my mind"
I forgot something
"to sleep on it"
to think about it more or take more time to figure things out, especially wait til' tomorrow
"when hell freezes over"
it's never going to happen or something that seems impossible
to be in hot water
to be in trouble
"I'm all ears"
I'm listening, I'm very interested.
"to be at sixes and sevens"
A confused situation
"a little birdie told me"
someone told me, but I'm not saying who it was.
"I could eat a horse"
I am extremely hungry and could eat a lot
"night owl"
Who is someone that stays up late?
"pig out"
to eat a lot
"It's a rip-off"
It's extremely overpriced.
"at the drop of a hat"
to act without hesitating or planning
"to get cold feet"
to think twice about doing something, to become less enthusiastic