Plushie and Erena's relationship is a complicated one so I will describe how each one feels about it here.

Plushie:
Plushie feels somewhat afraid of Erena's sexual advances but knows that she's doing what's right. She enjoys the feeling of being important and protected. She does have feelings for her sexually but kind of views Erena as a mother or big sister. At this point the thought of Erena is enough to make Plushie blush and Erena's scent is arousing to her. Plushie still feels a bit in over her head

Erena:
Erena thinks of Plushie as a fun toy that has to be protected. Kind of like a more important pet or livestock. She enjoys making Plushie happy just as much as she enjoys making her moan. She cares for Plushie as her mate and the mother of her children but will never see Plushie as equal to a dragon. Erena does not so much find Plushie's body attractive (though seeing her full does get Erena pretty worked up) as the idea of toying with her and making her feel good does. In conclusion she sees Plushie as an incubator, a submissive mate, the mother of her children, and an excellent squirmy cocksleeve.