We are a little too inclined to doff the thinking-cap at the first opportunity.
Now here's my idea that I evolved with my thinking-cap—I mean night-cap—on!
"And this head of mine would have to put on its thinking-cap," he pursued jovially.
Tell me what you know and then my 'thinking-cap' may be put on to some advantage.
I will try to tell one if you will let me put on my thinking-cap for a moment.
In his mechanical work his inventive turn of mind always caused him to put on his thinking-cap when he faced an obstacle.
But I had my New England "thinking-cap" firmly set on my shoulders.
There was nothing for it but to bow to the inevitable, break my journey, and put my thinking-cap on.