I don't think the basic BF smileys/emoticons have ever been clearly defined... and in my current state of procrastination, that seems like a terrible oversight.
-- General contentedness? Warm fuzzies?
-- Cheekier happiness?
-- Embarrassment? Melancholy? "Awwwwwwww...."?
-- Poking fun or actually mocking? A plain-text ": p" seems to be more mocking, but seems to be used here in a more innocent way.
Of the basic smileys, and seem to me to have the clearest meanings. As for the rest, I demand rigidly defined standards! Just think how many hours are wasted every year by members trying to decode the mysteries of ambiguously used smileys!