Prompter's comment:

Rainbow and Twilight had decided to stay indoors and enjoy some quality time together. While the fireplace crackles and warms the room, they started to talk about the things they have experienced together, all the fun memories and stories. Rainbow, as the humorous and funny pony that she is, had a lot of things she remembers vividly. They told stories and couldn’t stop laughing about all the great time and memories. Dash and Twilight realized how much fun they had together. They felt the deep trust they have in each other and how much they enjoy being together.

It is in moments like these where you can see the magic of friendship grow and feel a deep connection. They knew that no matter what happened, they would always have fun together.
These two ponies are more than friends. They are best friends.