I don’t know if this will be useful, or not, but Belle Robertson’s “small notes about Thanksgiving” email from this morning says
“if you need a time out, then you go to the bathroom and check something sober on your phone. you send an email to me or another sober support. you read a sober blog. you listen to a one minute message. if you’re feeling weird, you can go outside (either say you forgot something in the car, or that you’re taking the dog out, or both). if you feel yourself getting wound up for whatever reason, you can have a time out. just get up and leave the room. hide in the bathroom, do the dishes, go outside.”
So if you need a time out, you can come and post something here, about how [awful relative] is pushing all your buttons, or whatever, and take a breather.
And don’t offer lifts to anyone so you’re not on their timetable, either.