I think you're going to have to ease up on the hard liquor. Jack and coke can still taste pretty strong and smells strong for sure. The body is pretty good at getting us to avoid things it thinks are poisonous. I know bunches of people who have a kind of alcohol they can't drink anymore because they thrown up on it too many times. Can't say what's causing it in your case.

I don't have any personal experience with it so I can't help you further than that. Avoid smelling it and make sure that you breathe in before the shot, then chase and wait a bit before breathing out.