similar to a twihard, but much too old to pull it off. a twihard would be an older person, usual female, who has a fixation on twilight books, and or one of the stars, or the author of said movie, or book. the twihard would have friends, or daughter with whom to share such fixation.
a twihag would have the same type of fixation, but be over 60 and desperately alone with her obsession. after all, lets face it -- old hags don't get around enough to build up a network of similar crazies to share with.
it is assumed that a twihag would be very young at heart, or at least think she was young at heart. perhaps she would just be a little nuts?