Twilight and princess celestia spending some quality time together......i can see celestia being a mother/big sister figure to twilight to make her more comfortable after her move to ponyville (also she banished luna to the moon and was feeling lonely) and after they both became so close it kinda stayed that way... yep thats what i think.. oh and this is one of the ways i like to draw MLP characters but this is just one of the anime styles.