BLACK SABBATH - "iron man note" Tablature

the first chord is played like this:

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--2---------------------
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--0---------------------
then, u press down on the E-string, above the nut (do not think it works on floyd roses)
this creates a vibrato like effect, but the pitch decreases instead of increasing
so the open E falls below and then rises back up to the pitch of the E on the D string (but and octave apart)
this is right, because tony said so in guitar world......