The 'Groovy Part' down below is alot harder than it sounds. Start slow and build 
speed once your fingers remember how to slide up to the right places.

Intro:

G-----------------------|
D-------------5---------|
A-3-1-0-6-5-----5---5-4-|
E-----------4-----3-----|

Riff (lots of variation here, but it's eventually the same):

G-----------|
D-----------|
A-3---------|
E-----X-1-1-|

G------------------|
D-----5------------|
A-3-X---5----------|
E---------3--2-1-1-|

G----------------------------|
D-----------------5/10~~~~\5-|
A-3-1-0-6-5------------------|
E-----------4-3-X------8-----|

Groovy part (The slides up are really fast and are barely noticeable but they are 
worth practicing):

G-----------------------------|
D-7/8-8-----------------------|
A-------8/10-13---------------|
E---------------11-8--6-8-6-8-|

G-------------------------|
D-7/8-8-------------------|
A-------8/10-13-----------|
E---------------11-8--6-8-|