Uuuuuuh, I have no idea how to tag this. Is this technically pokephilia because Ditto is taking the form of Melony?
On Danbooru it's always tag what you see so even though we know it's a ditto that still counts as a meta knowledge since the act of sex is being made by the human form. So purely by what we see in the picture it's not pokephilia.
PO—No—Wah!Ya—Ditto!grind grindI want to get used to Melony, so transform into her! U——OFNaked?! T-that's not what I mea...!Ah!Champio~n! How ya doing? AhWhen I'm in front of Melony I get so nervous I can't talk to her...