Rainbow is a tired mom, trying to juggle work, training and kids together. She refuses to pay a nanny (like Twilight) or drop them of at her parents unless if it’s an emergency.
Rarity is taking her out for a day to relax, Rainbow looks like she needs a proper rest for all the things that’s happening in her life.
Rarity on the other hand can juggle work and kids pretty well. Living the busy life before having kids helped her to coop with it that’s for sure.
I’m going to be honest, I’m not happy of how I shaded Rarity’s mane or the highlight ob Rainbow Dash. I’ll try and experiment more with lights and shadows :>