A no must always be respected. There is no harm in asking a person to play.
In a play, the active/dominant/top part always carry the full responsibility for the wellfare and safety of the passive/submissive/bottom part.
"Circus" is the stop word! Circus means that the game has to stop at that moment. Anyone nearby the game has to monitor that the game stops or intervene.
Don't interrupt or comment on a game.