Russian obviously has a plethora of diminutive forms, but today I stumbled on what appears to be the opposite of that, namely for example нос -> носище, nose - big nose. Intriguing! But that's not in any grammar book I know and hard to find info on. How does that work grammatically? Does it decline? How? Is it productive (can be attached to anything)? Does it have different gender endings? A plural form?