How does Flower Gift Activate??

Question

>Flower Gift raises all party Pokémon's Attack and Special Defense stats by 50% in sunshine. The effect does not stack if more than one Pokémon has Flower Gift. Cherrim, the only Pokémon to have this Ability, also changes forms in sunlight, from a closed flower to one with spread petals; however, this is not caused by Flower Gift.

Source: Bulbapedia/ Flower Gift

Does Cherrim have to be out in the battle for this to activate??

• If YES, Can I just send her out and recall her yet still keep the boost??

What if she faints??

Answer 1

Yes Cherrim has to be out on the battlefield for the ability to activate.
No, you can't recall Cherrim and still keep the boosts.
If Cherrim faints, that means no more Flower Gift.