Had a little crazy idea for Xerneas that involves the fountain of youth. She had inadvertently created the legend with her "Fluids" after she masterbated in one spot after so long and not be able to do elsewhere due to Zygarde created the water that is pure life energy. So when the MC meets her and inflates her the water would go from clear to white for obviuse reasons. The fountain of youth then turns into the "Fountain of Fertility" where any female that bathes in the water ends up pregnant with a dozen kids. So when the MC revisits the region at the very end of the game he would see a lot more pregnant Pokémon and/or humans in that region where. Xerneas would love the idea that there would be more giant pregnant bellies in the world with that.
Each time Yveltal would try to pleasure herself she would kill her own mood to do it.