Light touch on my back causes brief electric shock-like sensation

Demographics: 25M, 165 cm, 68 kg, non-smoker, no medications, no major past medical issues.

I have a weird sensory phenomenon on a specific area of my back.

• Trigger: Light touch (like brushing or tapping)
• Sensation: Brief electric / shock-like feeling, not painful but actually somewhat enjoyable
• Other observations: Firm pressure doesn’t trigger it; if light touch continues, sensation fades (feels like nerve adaptation). Each new light touch triggers it again.
• Location: Mid-back, on the right side
• Duration: Discovered it in college when someone ran their finger on my back, but remember enjoying back rubs as a kid.
• Other symptoms: No numbness, weakness, rash, or skin changes

It's not an issue nor does it affect my life negatively whatsoever. Just curious what tit could be since no one else I know seems to experience this.

What's this called?