Electric Current, Connected, Physics Reaction

He removed his jacket, revealing a white T-shirt underneath. Before he could lift the hem of his shirt to remove it, Nian Xi stopped him. "You don't need to take off your shirt."

Jiang Yuning nodded and lifted the shirt to reveal his back.

His back was skinny and fair, like it belonged to someone who stayed indoors most of the time. It was weirdly pale, but now it was adorned with red patches tainting the blank canvas. She touched the red marks with her fingers, and he flinched.

"Painful?" Nian Xi felt bad. If the chair had landed on her, it could have seriously injured her. She was a girl, after all.

Jiang Yuning turned to look at her, his eyes reflecting hurt and protest. After a while, he wrote, "Ticklish."

Nian Xi was stunned. Why would it be ticklish? Was he easily tickled?

He wrote again, "Tingling."

She was silent.

He flipped his notepad to write, "Electric current, connected, physics reaction."