Idiomatic Expression

put your foot in your mouth
To make an embarrassing or tactless blunder when speaking:
to say something that is embarrassing or that upsets someone, because you have not thought carefully about what you are saying
“Rob tries to say nice things, but he always ends up putting his foot in his mouth.”
"Last night I was telling a joke, and I really put my foot in my mouth. I had no idea I was talking about Rob's wife."
"I am so embarrassed. Are you sure he could hear me when I was talking in the next room?" Reply: "Yes. You really put your foot in your mouth."
"Let's all be very careful what we say at the meeting tomorrow. I don't want anyone putting their foot in their mouth."

put your thinking cap on
to start to think seriously about how to solve a problem ; think seriously about a problem, in order to try and solve it
Let me put my thinking cap on and see if I can come up with an answer.

give sb the third degree informal
a situation in which someone tries to find out information by asking you a lot of questions ; to ask someone a lot of questions in order to get information from them:
• Look, I was out with friends - you don't have to give me the third degree.
Where have I been, who have I been with! What's this? The third degree?
If I'm even half an hour late she gives me the third degree.
I got the third degree from my dad when I got in last night.
a fifth/third wheel / feel like a third wheel INFORMAL
to feel that the two people you are with do not want you to be there;someone who is in a situation where they are not really needed or are ignored by other people
I don't have a role in the office any more - I feel like a fifth wheel.
• After Susan met Michael, I felt a little like a third wheel

put sb on the spot
to cause someone difficulty or make them embarrassed by forcing them at that moment to make a difficult decision or answer an embarrassing question ;to try to make someone do something or answer a question when they do not want to, by making them feel embarrassed not to do it:
• You shouldn't put friends on the spot by asking them to hire your family members.
Steve rather put him on the spot by asking when we were going to get a pay-rise.