The relaxation response also seems to increase the available level of serotonin, which is a chemical in the body that positively affects emotions and thoughts. While this information is promising, more studies are needed to directly confirm the relationship between massage and levels of serotonin in the brain.
The most common cause of scrotal itch is skin lesions such as psoriasis and eczema, when people can scratch so intensely that they make the skin bleed. But these conditions are of course visible and you say there is no rash, so we must think again.
One thing that is important in your case is that no visible rash or sores are present on the scrotum. Although the causes of scrotal itch are many like fungal infections, eczema, psoriasis etc but most of them present with a rash. Even eczema presents as patches of chronically itchy, dry, thickened skin.