Long Live Love
She doesn't smoke - but when she does, she doesn't inhale.
There's a pause between Bart and Uncle Jack when Eric and Serena tap tentatively on the door of Blair's bedroom and find her lying on the floor with her bare feet resting on the bedspread, smoking a leisurely joint and quietly assessing the ceiling. When they ask what she's doing, her reply is simple: 'trying to get closer to God' (in other words, trying to get closer to Chuck). She is drowning, so nonplussed despite Eric's presence that all she does is calmly inquire as to whether they'd like to join her.
Serena does for Blair's sake.
Eric does for Chuck's.
They form her walls, her sides; they hold her together as Blair smokes until the remnants are frizzy with use and her pupils are black and dilated.
Eric can't help thinking that this must be the reason that people talk about them (him and her, ChuckandBlairBlairandChuck) in hushed dark voices with reverent, irreverent looks: she's played dice with the Devil and won, and he's pulled down the last archangel and besmirched her white goodness with every colour of the rainbow.