1.In a bind - To be in a tricky position or situation.

I decided I needed to help my friends. They were in a bind and needed some assistance to get out of it.

Fred was in a bind and needed me to drive him home.

In a jam - To be in a difficult situation that may be difficult to get out of.

Her best friend was always there for her. She could always count on her when she was in a jam.

I think I am sort of in a jam.

In a nutshell - In a concise way.

It would take me a long time to explain the whole thing, so I'll just put it in a nutshell for you and be brief.

In a pinch - If necessary, for example, in an emergency.

I realized I didn't have one of the ingredients in the recipe, but I looked online and found out I could use a substitute in a pinch.

In a rut - Stuck in a mundane routine. Edward realized he was in a rut with his job. The work was boring and he wanted to look for a change.

In charge of - To have ultimate authority over something, someone, or a group of people.

Our teacher left the most responsible student in charge while he left the classroom for a moment.

In full swing - At the highest level of intensity or activity.

The summer season was in full swing at the tourist destination when they arrived for their holiday.