"But a corpsed subject wouldn't look good to paint, and standing still for too long is exhausting!"

Yes, corpsing and standing still are two completely different things. Performing arts, everyone! Buyo dance is related to Kabuki theater for a reason- it's an acting technique, dynamic stillness. And it takes more energy to maintain than sprinting.

Still! Just... endure it a bit longer. If the painting isn't impressive, she's gonna break his face.