"Remember what the doorman said, keep your head"

The story:

I only just found out. I'm convinced my version
makes more sense.
See, I though the 'keep your head' thing was a
very clever thing with two meanings, like 'keep
your temper' (as people were always saying to
Alice) and also a reference to the whole 'off with
her head' business.

Now I'm just confused about when the dormouse said
'feed your head' and what that's supposed to mean.
O.o