In my headcannon, Rainbow takes care of her on her way back home from the Time War between Daleks and Time Lords. And she did a better first job. Zero helping on her. She calls a crying Flurry by placing her on her chest so she can hear her heartbeat since heartbeats calm babies. And she plays with her. And changers her diaper. And tickled her.
And it’s one of the reasons Twylight got jealous of R along with her fame. But Flurry made it clear ny.pictures Rainbow can zero replace Twylight. And Flurry also uses a picture of the Mane ones to remind them of their bond, proving she inherit her mother’s heart of gold.

This I want to see.
It be sweet if she took care of dear Flurry. And she pays more attention contrary to Twylight who zero did on her first time. And isntead of yelling, Rainbow comforts Flurry by placing her on her chest so she hears her heartbeat. Babies enjoy heartbeats which calm them.