I spy with my little eye a parafusion set. Please don't give people the idea to use this thing as a Liepard.
As for cott:
(big ass pic is big)
Whimsicott @ Heat Rock
Trait: Prankster
EVs: 252 HP/252 Def/ 4 SpD
IVs: 0 Speed
Sassy Nature
Moves:
- Sunny Day
- U-Turn/Memento
- Encore/Taunt
- Stun Spore/Light Screen
Weather support Whimsicott. I used the standard physically bulky EV spread with a Sassy nature and 0 Speed IVs so that you can get a somewhat slow U-Turn. It works like Liepard does in NU: Thanks to Prankster, Whimsicott is guaranteed to get a Sunny Day off. U-turn is used to gain some momentum and get in sun sweepers safely against anything that outspeeds, but if you don't need cott to set sun more than once you can use Memento to ensure safety for your sun sweeper (which is useful if you're using a Growth + Chlorophyll abuser). Encore allows Whimsicott to come in on something and lock it into a useless move, whereas Taunt prevents other Pokemon like Ferroseed from setting hazards up on her (or boosts). The last moveslot is up to you: You can use Stun Spore to spread paralysis, but considering you probably want to use sun in tandem with Chlorophyll sweepers who will outspeed pretty much anything anyway, you can also opt for Light Screen to increase Cott's special bulk and to allow sun sweepers to come in on dangerous special attackers. It's up to you, though: Leech Seed or Giga Drain can be used to replenish some of Cott's HP (having no lefties kinda stings), Knock Off can be used to further annoy the opponent, Swagger can be used if you're feeling like a dick and love parafusion, that's all up to you.
Overall, Prankster plus a wide support movepool makes Whimsicott and excellent sun setter.