Love, Swings, and Hospital Things.

Stiles tries to show Derek how fun human life can be by taking him to a playground, where their innocent swinging session quickly turns into a chaotic makeout session that ends with Derek breaking his arm.

Now, at the hospital at 2 a.m., Stiles is forced to explain the situation to his dad, Sheriff Stilinski, who isn't exactly thrilled with his son's late-night misadventures.

Despite the chaos, Stiles and Derek can't help but laugh at the ridiculousness of it all, and Stiles is already looking forward to another round-this time with Derek's healing powers back in action.