It is not confirmed, but the first mention of a whuffle seems to be this one.
Initially described as such: The trick to a good whuffle is to breathe in and out quickly, like a dog smelling something really interesting. If you like, every once in a while you can exhale forcefully to get rid of accumulated air, again, like a dog will do. This usually makes the whufflee giggle. To make sexy whuffles, you go slower, on more sensitive parts of the face and neck. Include the ears, maybe lick the earlobe, and say "mmmmm".
A whuffle is usually performed on the face and/or neck area, but can be administered anyplace the whuffler sees fit.
Can also be performed via text message.
WHUFFLES also is an actual command in MetaChat: "Wishing Happiness Und Friendliness Freely Lest Everybody Suffer"