Itch.

Somewhere between pleasure, and pain, it is a common sensation that irritates one when unresolved.

Itch strikes when wounds are healing, where insects have bitten, and most of all, for no logical reason at all. Which makes one wonder why does a healing wound itch when its supposed to want to reduce any further damage to the injury.

Pleasure is when an itch is scratched, and continued scratching provides continued pleasure, until the skin finally breaks and it descends into pain.

So sickening i tell you.