I liked the Postal 2 noise and the animation is very disgusting, which is nice. The problem you're having is that the pairing of visual and sound is important in making something truly vile.
The music, while "matching" the visuals, makes it feel empty. When the finger stretched I'd add either rubber being stretched or egg shell breaking SFX. You can use a free sound library or, if you have a microphone, make your own and get creative!