You can't really play all of it on a 4 string unless you tune to A
and just play on the higher frets on ur Hi-C string. But you can play
the first few riffs if you tune down a step to (D,G,C,F). Just play
the 5th fret notes on the higher string as open and the 7th fret
as 2nd fret.

Korn - Porno Creep
(A,D,G,C,F)

Riff 1:
C|-----------------/5--|
G|----------5--7-------|
D|----5/7--------------|
A|--5------------------|

Riff 2:
F|------------------------------7--------|
C|------------------5-----7--------5-----|
G|-----------5--7---------------------5--|
D|-----5/7-------------------------------|
A|--5------------------------------------|

Riff 3:
G|------------5--7---------7--5------------5--|
D|-----5/7-----------------------7----5-7-----|
A|--5-----------------5-----------------------|

Riff 4:
G|------------------------5/7p5-----|
D|----------3---5-5h6h7----------5--|
A|--3h4h5---------------------------|

Riff 5:
G|--5h7--------------------|
D|---------5h7-------------|
A|---------------3h5--5h6--|

Riff 6:
F|--9--7---------------------------------|
C|----------9----8----7------------------|
G|---------------------------------------|
D|-------------------------------3h4h5b--|
A|-------------------------3h4h5---------|

Riff 7:
C|----------9---8---7----6---5----4---3--|
G|--7h8h9--------------------------------|

Riff 8:
G|------------5--7---------7--5---------5h7-------5h7--|
D|------5/7----------------------7--5h7------5h7-------|
A|--5------------------5-------------------------------|

Riff 9:
G|------------------5h6h7---7h8h9--|
D|--3h4h5---5h6h7------------------|

Riff 10:
F|-------------------9--|
C|------------7h9-------|
G|----------------------|
D|--0-------------------|