Dunno about happy while it's stuck, but sedate is what El will be going for. It's not a complicated plan: essentially, spamming Snooze spells at the dragon in hopes of helping to slowly calm it if not actually put it to sleep. His Luminary power hasn't fully recovered yet, but he could also try his hand at turning small parts of the dragon (quite!) temporarily to metal in an effort to help immobilize it for resizing/transfiguring if needed.

as your questionable resident dragon expert El will basically be making assumptions based on his working knowledge of Boreal Serpents from his world so. Effectiveness with things may or may not add up. they only have a 25% resistance to sleep so Ahem.

Given this is a prolonged tactic though, gonna need some distractions and protections while the Attempt Is Made if characters are on board with the idea. I expect after expending his mana pool, successful or not, Eleven won't remain conscious to see much of the results /popcorns