The idiom "in the loop" means to be aware of something, especially a current situation or development, as it happens. It can also mean being included or involved in a group or activity.

The idiom "pour cold water on" means to ruin someone's plans or destroy their mood by introducing an unpleasant or unwanted element into the situation. It is used to express disappointment, frustration, or a desire for something more positive or agreeable.

The idiom "in a nutshell" means to summarize or describe something briefly, usually in a concise manner that captures the essence of the topic at hand. It is often used to give an overview of a complex situation or idea, and can be used in both formal and informal language.

The idiom "crash course" refers to a rapid, intensive, and comprehensive learning experience that covers all the important topics or skills necessary for a particular activity or goal.

The idiom "a rolling stone gathers no moss" means that a person who is always on the move, traveling or working, does not accumulate responsibilities or obligations. It implies that such individuals are carefree and do not have any commitments that weigh them down.