Song Xiaodong and Song Xiaoru chatted for a while before going to sleep, not mentioning again the fact that they weren't related by blood. They interacted just like before, still as close as siblings.
Everything seemed normal before sleep, neither Song Xiaodong nor Song Xiaoru would have thought anything would happen between them, but when they woke up in the morning, something utterly unexpected occurred.
The summer weather was hot, and even if Song Xiaodong and Song Xiaoru slept in the same bed, they usually kept to their own sides, because cuddling together would be too warm and uncomfortable.
But now, as the weather turned cooler, and before the heating was turned on, if the air conditioning wasn't on, the room temperature would barely exceed ten degrees, which was fairly chilly.
Therefore, the two of them sleeping together naturally ended up cuddling throughout the night.