Well, the easiest way to go would be to make it a potion. Like the "blending in" potion Harry did in FM. Drinking the potion would place the aspect "Emotionless" on your character, and it would last for one scene. Usually, a maneuver requires 3 shifts minimum, but if your character is prone to emotional outbursts, I would increase it a bit, depending. 5-6 should be enough in any case, I think. The duration for thaumaturgy spells usually starts with "one scene", which should be enough, at least in my book. It isn't too much of a stretch to brew a potion like that, and there are all kinds of ways you can compel the aspect on the character, which I would enjoy doing (again: see FM)
The block would be feasible, too, but since you basically want to meet with the WCV without him using his mental powers on you, that is handled way better by an aspect and a resulting tag for effect, plus a bit of bargaining with the GM. Especially, if he is doing something hectic and drastic (like getting rid of every emotion), that should have an impact much deeper than just a block.