a sack to put the feathers in
A big bag you use for bird fluff, but also a way to describe a woman who makes your brain go soft.
That girl walked in, and I felt like my brain just melted into a bag of feathers.
He said she was like a sack for feathers, but I said she was more like a sack for my heart.
My teacher called the new girl a 'bag for fluff' and I got in trouble for laughing too hard.