i have to search for clips on youtube
I couldn't find the relevant bit on youtube, but here's the script.
Ebeneezer Blackadder: Well, I’ve got all the presents…
Baldrick: …and I’ve nearly finished the Christmas cards.
Ebeneezer Blackadder: Oh, splendid! Let me see… [opens up a card he has picked up from the desk] “A Very Messy Christmas.” I’m sorry, Mr Baldrick — shouldn’t that be ‘merry’?
Baldrick: “A Merry Messy Christmas”? All right, but the main thing is that it should be messy — messy cake; soggy pudding; great big wet kisses under the mistletoe…
Ebeneezer Blackadder: Yes… I fear, Mr Baldrick, that the only way you’re likely to get a big wet kiss at Christmas — or, indeed, any other time — is to make a pass at a water closet. However, be that as it may… [Baldrick gives him the card again] “A Merry Messy Christmas.” ‘Christmas’ as an H in it, Mr Baldrick.
Baldrick: Oh…
Ebeneezer Blackadder: …and an R. Also an I, and an S. Also T and M and A… …and another S. Oh, and you’ve missed out the C at the beginning. Congratulations, Mr Baldrick! Something of a triumph, I think — you must be the first person ever to spell ‘Christmas’ without getting any of the letters right at all.