I wouldn't go so far as to say that it actually backs Advanceshipping but its one that in no way interferes with it. If Manaphy rejected Drew from being next to May, then it would support us. Actually it would be kinda funny to see Manaphy swap Drew with someone else's body to keep him away from May (Harley would probably be the best choice).
"The hardest thing about dreaming about someone you love is to wake up but if the only place I could see you was in my dreams I would sleep forever"
Actually it could be used to back advanceshipping. I.e. as someone from Serebii said:
If Manaphy is the Prince of the sea, and May is the mother wouldn't that make her the queen of the sea?
and well whoever wears the sea crown is 'the king of the sea' as Ash did, that guy in the movie said, "and whoever shall wear the Sea Crown shall be named king of the sea"
You're born, you take s-. You get out in the world, you take more s-. You climb a little higher, you take less s-. Till one day you're up in the rarefied atmosphere and you've forgotten what s- even looks like.