In what circumstances does or would your character drink alcohol? (e.g. "with a meal, for fun, when depressed, at any excuse, NEVER EVER")
Oh geez, he probably wouldn't ever. But... if he were to feed on someone who was drunk, let's say he would probably catch the drunk from them. If there were magic alcohol he could drink... probably if he were upset. Or possibly out of curiosity.
How much would they normally consume? Do they get drunk every once in a while, or live and breathe alcohol, or make sure to stay under the legal limit?
Probably not much.
How much alcohol tolerance do they have? Does even a sniff of alcohol knock them over, or can they guzzle alcohol without feeling impaired?
I would say about zero. Having never been exposed to it, he'd get through one and be no good to anyone.
What kind of drunk is your character? How would they act if they were drunk?
I think he'd be a very quiet drunk. And maybe a little affectionate (e.g., sitting beside someone he feels good about and just being a bump on a log but occasionally watch them like they were the only person in the world). Though if someone were to bring up a topic that upset him, he could probably get very upset very quickly.
Who would they go drinking with if they had to choose drinking buddies?
... Aidou, probably. Or Yuuki or Hikaru. Probably not Suzaku because he likes him too much.
What's their alcohol preferences? Beer, wine, mixed drinks with fancy names?
No preference. He might like red wine though, for the color.
Green alcohol y/n?
I thiiiiink no.
Your character is completely drunk. Who do they drunk-dial, and what do they say?
He'd drunk dial Subaru (aka the Prison) and start rambling about how Subaru would like everything about Marina.