What if the move it chooses for the second move is random? That way you don't have to select another attack.
Cool. You should make an ability variant of this cause I can see this being an ability as well.New Item: Harness Unit
"A harness worn for adventuring. Prevents the holding Pokémon from landing critical hits, but boosts the power of its moves."
- Prevents the holder from landing critical hits. In return, each of the Pokémon's moves has its power increased by 20%.
It would work the same way it always did. Go into the air the first turn(cause remember the second attack still counts as the same turn) then come down the second turn. Charge the first turn and attack the second etc.
If you also want to know what happens in a double or triple battle if a pokemon was charging and another pokemon used Dualize on it, the charging Pokemon would unleash it's attack in that same turn and that will count as it's second move.
Edit: scratch that first part that makes no sense, I think it would make more sense that they are unable to move the second turn regardless of using fly or sky attack, sorta like slaking using a two turn attack with truant.