When you slide from 4 to 6 don't play 6 just slide back to 4 and play
Same for 6 to 8 and 2 to 4 and 4 to 6.
If you use this method this is the perfect way to play the intro

e-4-------------------
b-6-------------------
g----2--4/6/4--2/4--22
d----4--6/8/6--4/6--44
a---------------------