Transformations for Pokemon Mates

19 year old Ash Ketchem found himself in a white room filled with legendary pokemon. He knew something was up. He didn't know if he wanted to be a part of it.

'Ash, my chosen one.' Ash turned around to see Arceus, the creator of all Pokemon. "Arceus!" Ash quickly exclaimed, falling to the floor, bowing. 'There is no need, Ashura. Please, get up.' Ash quickly got up.

"Ummm... why did you bring me here?" Ash inquired, suddenly noticing a blush from some of the Pokemon behind Arceus. 'You've saved the world more times than many could count, and you've never been rewarded.' Arceus stepped aside. 'I will allow you to pick one of my sons or daughters, or...um...myself, to have as your mate for eternity. I know you've always had a thing for Pokemon.'

Ash blushed intensely, feeling trapped, knowing that the highest pokemon of all knew his kinks. "Y-yeah, you're right" he stuttered. "But poképhilia is frowned upon, and-"

'Not for you. I will turn you into the species of which one you kiss. And, if you wish, i could even change your gender.'

This was news to Ash. He could pick any of them? He could become a she? This was a hard choice for sure. Or, at least it would have been if Ash hadn't already chosen his mate. He quickly walked over to the Pokemon he loved called...