Of course there are times where it is ok, such as when it is explicitly written into a script, or an improv show, or a one person show that is a narrative more than a play. But generally in a scripted play or musical, the cast should not be directly interacting with their audience. Yes, they should allow for laughter or other responses (gasp!) from the audience, but to directly interact with an audience member (to sit down with them and talk about what happened, or to mug to the audience) in the middle of a scene is usually not going to be acceptable.

A couple shows where it is scripted where a character can interact with the audience would be The Complete Works of Shakespeare (Abridged), or the narrator in Into the Woods, or Nunsense. Mike

Thank you.