not enough room to swing a cat

If there is not enough room to swing a cat, that means you are in an awkwardly small and confined space which is very uncomfortable to be in, especially if you are stuck in this small space with another person. The idiom used for a small space which is uncomfortably awkward is somewhat of a colorful phrase and not too appropriate, since you are speaking of swinging a cat but it sends a message to how small the room or space really is.