Wassailer

[Sarah]

One who drinks wassail; one who engages in festivity,especially in drinking; a reveler.The rudeness and swilled insolence Of such late wassailers. Milton.

[Mary Mallozziberg]

especially in the past, a person who takes part in the activity of going from house to house at Christmas time singing carols (= Christmas songs) , traditionally drinking wassail (= warm beer or wine with spices added) :