After the hell that was Satori's fight, the Youmu/Yuyuko fight was a pleasant refresher thanks to Poison Arts.
I wanted to pick up P-Mist and Hellclaw as interim skills until I learned P-Arts.
First round
Alice: Puppet Control(or w/e, parrar's spellcard version)
Byakuren: DEF/RES Down -> Yuyuko
Reimu: Defend
Satori: Poison Arts(Tags Youmu successfully)
Sakuya: Jack the Ludo Bile -> Youmu(2 hits!)
Repeat ad nauseam until Youmu dropped, and Yuyuko got venom'd.
Once Youmu dropped, I went all defense until the venom did it's job.
Avoided Res. Butterfly, which Satori can't learn(And thus, it's useless.).
And on the note of celestial peaches....
My Face after getting a 3rd from a drop:

My Face after a 4th: :3
My Face after 3 more: :]
My Face after 2 more after that:

"Peaches! Peaches Everywhere! Hello peaches how are you? Fantastic!"
Needless to say, even after making the bombs gohei, great maid, fencer dress, viper clothes, sacred miko clothes, The Green Eyes(to boost poisoning), and the Shanghai Greaves, I STILL have plenty of peaches!
...But I'm short an Iron to make Youmu's current strongest sword. I COULD make the one that has a chance at instant death but...Right now she needs to be able to keep up with Sakuya, and that sword's the key.