Inside the booth
Suggest listening in a portrait sequence
Use attention without inventing a real conversation.
A slight turn and a reaction can imply that someone has heard something offscreen.
Keep the action simple
Start facing the lens, look toward a nearby point, react and return. Avoid tilting so far that the face leaves the crop. For a pair, decide who appears to speak and who listens using small expressions rather than tiny written dialogue. Keep the pose optional and comfortable.
Describe it as a creative idea
Review the sequence and choose an original playful caption if wanted. Do not frame the result as evidence that the people actually had a particular conversation. Preserve the full strip; a single extracted reaction can imply a different story from the one participants intended.