What happens next?

How to visit friends that smoke when you are a non smoker
Be honest.
One way to deal with the situation is just to broach the topic directly. Bring up that you'd appreciate it if they don't smoke around you.
It's also helpful to back up what you're saying with reasons why you don't like having secondhand smoke around. You could say, " i know i'm a guest here, but i'd really appreciate it if you didn't smoke around me while i'm here.