What do you mean by turning on the air conditioner?

This sentence means that a boy wants to date a girl.

"Turn on the air conditioner" is a network term. This kind of expression is more implicit and will not directly tell the boy's intention. When a boy wants to date a girl, he may invite her to some intimate activities under the pretext of "turning on the air conditioner". This expression is obscure, but girls usually understand the meaning.