Does Obama (or any President) shave himself?

[Larry the boss]

I shave them

[bojangles1987]

Lulz.

What does the first lady actually do - I mean legally, does she have a role?

Or is her job as any wife's is, to polish the tip?

Differs from First Lady to First Lady. They have power of some kind, and all use it in some way, but usually always differently and some use it more than others.