How do I get a staff?

Hint 1 of 8:

The magic staff you're looking for is pretty much in plain sight.

Hint 2 of 8:

It's in Unseen University.

Hint 3 of 8:

It's the one that Windle Poons is holding on to.

Hint 4 of 8:

He's really a rather absent-minded kind of guy.

Hint 5 of 8:

He probably wouldn't notice if you switched his staff for something else.

Hint 6 of 8:

Just look for something that's about the right size and shape.