Couldn't lie straight in bed Australia New Zealand informal
To be dishonest or deceptive; to lie a lot
Don't care about what John has said. That guy couldn't lie straight in bed.
No one believes what she is saying to be true as she couldn't lie straight in bed.
White lie
Seem to be very suspicious or morally unacceptable
Used to imply that someone is acting as if he or she is demure, innocent, sincere or reserved but they may be not
Very dishonest and deceptive
If someone has a cast iron stomach, they have a strong stomach that can digest unusual food and even bad food without being ill.
Jimmy must have a cast-iron stomach, when he drank milk with lime juice and felt perfectly fine afterward.