The After-Bath

Since on a roll with these terrible puns:

 Olivia in her appropriated butterfly towel 

(which used to be Elsie's, officially,
but was commandeered by her older sister).
You can't make her like monsters or make her dislike pink.

 Elsie in her sister's cast-away Monster towel,
which she affectionately calls "Kitty, Miao"
probably due to the two orange horns on top (not pictured)
which could resemble ears...
I like the teeth, especially.