Well, personally I would either not bother replying, or just respond "Fine thanks", no asking how she is or anything that could further a conversation you don't want.
Though if you had the balls to do it, a picture message (they say a picture paints a thousand words, LOL) of you sat reading CoC, next to some Xmas decs, tucking into a plate of black pudding, with a demonized Smurf on your shoulder, would sure do the job!
See you tomorrow!