Here's some serious Santa Clues for you to be chewing on:

My first is in Santa and Claus they say
My second's in reindeer but not in sleigh
My third's in Underhill but not in Freda
My fourth is in follower but not in leader
My fifth is in fourth but not in third
My sixth is in dicky but not in bird
My seventh - no clues: it may not exist:
Are there just six - or twelve - in my list?
I hope that my clues don't cause you to chunder
Tempted and tried, we're oft made to wonder.

F.U.S.S. (Santa Clues)