Examples:

• The attic was so small there wasn't enough room to swing a cat.
• The tiny apartment felt like a sardine can; there wasn't enough room to swing a cat.
• His mind was so cluttered with thoughts, there wasn't enough room to swing a cat.
• Trying to work on this tiny desk is like trying to swing a cat in a phone booth.
• I'm so packed in this car, I don't think I could even swing a kitten.
• The cramped closet was so small, you couldn't even swing a cat without hitting something.
• This room is even smaller than the one we saw yesterday. There's no way you could swing a cat in here.
• His schedule is so packed, there's not enough room to swing a cat, let alone relax.
• His heart was so full of love, there wasn't enough room to swing a cat.
• The tiny bathroom was barely big enough to swing a cat, let alone take a bath.
• I'm so packed in this elevator, I don't think I could even swing a mouse.
• The cramped kitchen was so small, you couldn't even swing a cat without knocking over a pot.
• This apartment is even smaller than the one we saw yesterday. There's no way you could swing a cat in here.
• His mind was so cluttered with thoughts, there wasn't enough room to swing a cat.
• Her heart was so full of joy, there wasn't enough room to swing a cat.
• The tiny bedroom was barely big enough to swing a cat, let alone sleep comfortably.
• I'm so packed in this car, I don't think I could even swing a mouse.
• The cramped living room was so small, you couldn't even swing a cat without hitting a piece of furniture.
• This house is even smaller than the one we saw yesterday. There's no way you could swing a cat in here.
• His schedule is so packed, there's not enough room to swing a cat, let alone take a break.