I like to think of Celestia as the fun aunt.

I thought it would be kind of cute if Fluttershy and Discord's kid was having some trouble controlling her strength in her magic, so she took several days of a visit to Celestia's castle to learn harmony lessons from her to learn to control her power and reign it in. She learned so much from her, being she stands for harmony and Luna helped her as well. She likes to think of Celestia as an aunt figure. She spends a lot of time with Celestia and Sombra's child as well. (Sombra from the IDW comics that is! lol)