What does it mean when the whipping and dripping of wax oil are mentioned in The Sheep-Herding Star?

Tianqi was misunderstood by the police as the wolf of handcuffs. In order to help Tianqi solve the problem, Axing made it up. He said that they were boyfriend and girlfriend, and Tianqi had handcuffs because Tianqi liked to be handcuffed. Beside the bed, they were whipped by Ah Xing and dripped with wax, and then the police let them go

The method of abusing people, whipping is easy to understand, dripping with wax is to take off people's clothes and then light candles. Dropping wax oil on people drop by drop, I don’t understand what it feels like