To be sleighed is to be immeasurably drunk on Christmas Eve, so much so that you are either still drunk Christmas Day or are massively hung over. The same as "wasted" or "shit-faced" but used specifically on the Christmas Holiday. This term can also be used post-Christmas if one is wasted Christmas Day and continues into Boxing Day.
This is often seen in "mall Santas" after they finish thier final day on the 24th.
Guy 1: "Whoa, did you see that mall santa tossing his guts under that tree?"
To give a simple task to someone highly over-qualified - originally finding the best percussionist available to play sleighbells in the chorus of a Christmas song.
Have you seen Jay's art? He's too good to be painting sets. I see some sleighbelling going on...
Jay's been sleighbelling with the choir again. He's a Grade 8 and they get him on a part that a toddler could play.