It sounds like Jack recorded the second guitar playing riffs in the background with either a slide or whammy pedal,
and then reversed it, for the following reasons:
1) The notes get louder towards the end of each riff, as opposed to dying away
2) The frets are inaudible

Second guitar settings:
Amp Settings: High bass, low middle and treble, medium gain and lots of reverb.
Guitar Settings: Pickups forward, low tone.

GUITAR 2 RIFFS (remember, these won't sound right unless they are reversed):
   RIFF 1    RIFF 2            RIFF 3            RIFF 4
e|-5/17------------------------------------------3h5b6-b5p3p0--
B|-----------20/7-7-7-7/3------20/0----------------------------
G|-------------------------------------------------------------
D|-------------------------------------------------------------
A|----------------------------------4-4-4/0--------------------
E|-------------------------------------------------------------

INTRO:
A5 G5 A5 X X

BREAK: Played 3x
A5 G5 A5

RIFF 1: Played 2x

VERSE 1: P.M.
A5                               RIFF 1
There's a little girl who says, "Ping! Ping! Pop!"`    `A children's joke that doesn't "bear repeating"
			        RIFF 1
There's a little girl who says, "Ping! Ping! Pop!"
   G5 RIFF 1
Hello
      A5 RIFF 2
Oh, oh

RIFF 1

VERSE 2:
There's a little boy with a spider in his hand
There's a little boy with a spider in his hand
      RIFF 3
Hello
Oh, oh

RIFF 4

BREAK: Played 4x

VERSE 3:
There's a little girl with the red shoes on
There's a little girl with the red shoes on
Hello
Oh, oh

VERSE 4:
There's a little boy with twenty-five cents
There's a little boy with twenty-five cents
      RIFF 4
Hello
Oh, oh

VERSE 5: Combinations of RIFF 1 in this verse
And there's a little girl with a tiger on her bed
There's a little girl with a tiger on her bed
Hello
Oh, oh

BREAK

VERSE 6:
There's a little boy with nothin' on his mind
There's a little boy with nothin' on his mind
Hello