Actually, Lady Edwina heartily endorses the concept of grass regurgitation! ALthough ALWAYS outside.

(She won't tell you this but she makes a decidedly undignified noise that is NOT a meow as she prepares to cleanse her tummy!)

Edwina eats grass and then makes a chocking noise that never fails to frighten me. I too, have heard this is good for cats as it helps prevent hairball blockage.