#2
He pulls his neck towards him so he puts more tension on the strings, it's a way to bend a note up. If he had a floyd rose type of bridge you wouldn't need this trick.
#3
I think he's pushing down on the string between the nut and the tuning peg. It tightens the whole string so its kind of like a bend. He might have used it to get a better sustain on the harmonic he plays while he does it.
#4
Quote by ioAK47oi
I think he's pushing down on the string between the nut and the tuning peg. It tightens the whole string so its kind of like a bend. He might have used it to get a better sustain on the harmonic he plays while he does it.

I agree, looks and sounds like he's doing this.

Check out John5 if you want more behind the nut bending action.