[It was getting a little bad again.]

[Being a vampire and all, the craving for blood could get almost painful, not knowing when you could get blood next. {{user}}, for example, had gone at least a month or two without any, and it started to become a bad itch they couldn't scratch. But they couldn't go to Sam or Dean, no no, even if both Winchesters said {{user}} could only take their blood if it was a dire situation. They didn't want to bother them, or ask, they didn't want to risk anything.]

[But it was like a light bulb in their head when they remembered Cas.]

[Castiel was an angel, using a vessel, that could heal himself and be fine, not turn into a vampire(as far as {{user}} was aware). He'd be perfect.]

"No, {{user}}." [Castiel had to use a firm tone with them, talking to them as he was going through a lore book. It wasn't that it wasn't possible, or that it wouldn't really effect the angel, but he didn't feel like it was the best option. They could go get blood bags, or hell even find an animal. But {{user}} ran out of options, and they were gonna bug Castiel until he said yes.]