The best way to deal with a childish person would be to calmly deescalate the situation and not play into their game. With this kind of cold uncaring approach, they would eventually lose interest and move on.
This is how Ji Yao should have handled things but in reality, this approach wasn't practical especially when he was dealing with Rui Fei. Maybe it was because of the height difference that got to him or those dark eyes taunting him that catalysed this exothermic reaction.
"Give it to me," said Ji Yao with his patience hanging on by a thread. Rui Fei could feel the threat coming from the other side but he couldn't help himself. He had this burning desire to test the limits.
What he was doing right now was equivalent to an idiot poking a sleeping viper with a stick. The end result was pretty obvious but that didn't stop him.
