Some comments I've seen:
"dashing through the snow in a space wolf open sled over the warp we purging all the way yay"
"On the 12th day of xmas the emperor said to me
1 heretic burning
2 orks boinking
3 xenos dying
4 worlds are turning
5 warps a storming
6 marines are dying
.... And a space wolf riding on a sleigh"
"Does he decide if the zenos have been naughty or nice"
"And every year on fenris the man on the sled comes and delivers flying boxes to all the little scout troopers"
"The wolf in the foreground has the same facial expression as Snarf in Thundercats"
" I can hear the conversation now...
Logan "Why are they laughing at me? I'm one of the deadliest Space Marines in the Galaxy!"
Space Wolf Grunt "I don't know sir, snicker, your new sled thing looks great! Snicker snicker"
Logan "You're laughing at me too!"
Grunt "No sir, snicker, really I'm not, it looks great sir, really, snicker"
Logan "Sod this, I'm going home!"
Grunt "No sir, don't do that, they've got a Helldrake, if we win you could have turkey for dinner"
Logan "Sod off!"
Grunt "Jingle bells, Jingle bells, bahhhahhahhhahahha!""