Use "until s.o. is blue in the face" when someone is trying to convince or persuade another person to do something, but he/she won't agree to it. "You can ask John until you are blue in the face, but he won't let you drive his new car." "I talked to the teacher until I was blue in the face, but she wouldn't let me take a make-up exam." Blue in the face = I think the face is blue because the person is talking so much he doesn't have a lot of oxygen. In spite of the effort, he won't succeed.

I used to ask my teenage son to clean up the mess in his bedroom until I was blue in the face. Now I don't bother.

it means until you are blue in the face if you say something until you are blue in the face, you keep saying the same thing again and again but no one listens to you. I can tell him to tidy his room until I'm blue in the face, but it's always a mess. cowboy...

'Do something till you are blue in the face' is an idiom meaning 'to try do something -such as convincing others of something- as hard as you can but without success or until you feel exhausted': 'I talked / argued until I was blue in the face, but I couldn’t change her mind.' 'She had to talk until she was blue in the face in order to persuade him.'