I couldn't feel, so I tried to touch

Backtagging: Always!
Threadhopping: Always fine on the network, ask me and the other player involved if it's in a log.
Fourthwalling: I'd prefer characters didn't know about Supernatural the show, but the Supernatural books by Carver Edlund are fair game, as they exist in-setting. If you want to take advantage of that and need more information in order to work out the details, I'd be happy to help!
Offensive Subjects: As long as everything's got adequate warnings, things should be fine!

Pronouns: Castiel has no preference but is currently possessing someone with unambiguously masculine presentation, so feel free to have your character assume he's male. Feel equally free to not do that too, though. Castiel doesn't care. He/Him/His pronouns will be used in prose for the sake of clarity and consistency.
Hugs: He's probably not going to hug back, but you can try.
Flirting: He's definitely not going to flirt back or understand what you're doing, but you can try.
Kisses: Same as above, but even more awkward.
Sexuality: You can ask, but the answer is definitely going to be no.
Fighting: Please fight Castiel he probably deserves it
Injury: Let me know so we can plot things out but the answer will probably be yes.
Death: If you've got a good idea then absolutely let me know!

Castiel is an angel of the Abrahamic triad of faiths, and comes from a universe where the Abrahamic God is both absent/indifferent and exists in tandem with all of the deities of Earth's various religions, all of which appear to be "correct" to at least some degree. I fully realize that this could bring up some uncomfortable or offensive situations, and though I will be doing my best to handle them respectfully I understand if some people would prefer not to deal with that at all.

Leave a comment with your preference below and I'll either take care to avoid certain subjects with your characters or avoid tagging them altogether, no questions asked. Comments are screened.