A sort of banter where two people have a convo about something which they both know is total bullshit, back and forth, to the point where they're not sure whether to believe each other or not.
"we haven't spoken for ages"
"its a crime!"
"we'll have to run off together, get away from the police!"
"yeah, how about new york"
"sure, and we can go line dancing in cowboy boots"
back and forth, scoring bullshit tennis points for random examples