fuka-fuka(フカフカ)
fuka-fuka describes a soft, springy, and cushion-like state, typically used when something has a plush, yielding surface that gently compresses under light pressure.
fu(フー)
1. the hissing sound made by a cat
fuwa(フワ)
1. Light, soft, or airy state
fuwa-fuwa(フワフワ)
1. Soft, light, and fluffy in texture