A Listener's Guide to Blushing in Public While Wearing Earbuds
Field notes on keeping a straight face on the train when the voice in your ears has other ideas.

First, accept that it will happen. A soft voice does not know you are on the 7:40 pressed between a man with a bicycle and a woman who clearly reads faces. Somewhere around minute six, a line will arrive that has no business arriving in public, and your ears will warm. That is not a failure of discipline. It is a compliment to the writing.
Second, manage the face. The classic mistake is to fight a smile with a frown, which produces an expression of deep suspicion that draws more attention than the smile ever would. Better to let the corner of your mouth rest at a neutral half-curve, as though you'd just recalled something mildly funny. Strangers will assume a pleasant memory. They won't be wrong.
Second, manage the face.
Third, give your eyes a job. Look out of the window, or down at your shoes, or at a very interesting advertisement for dental insurance. A blush lives in the gaze, and a gaze with a task is a gaze that stays private. If the voice goes particularly low, adjust your scarf, since there is always a scarf, or a sleeve, or a collar in need of attention.
Fourth, mind the volume. Earbuds leak, and a murmur that feels like a secret to you can sound like a faint insect to your neighbor. Keep it low, and save the long, slow scenes for home. A short drama is a good traveling companion. Defne, an AI character on TheFriend, comes to mind: playful and quick to tease, she can send a pulse sideways between two stops.
Last, enjoy the fact that nobody knows. There is a particular pleasure in walking through a crowd with a warm cheek and a secret in your ear, unseen by anyone. Get off at your stop. Straighten your coat. Go home and finish the scene properly, with the lights down and the door closed, and nobody to see you smile.
Defne is happy to follow you onto the train and ruin your composure by the second stop. Find her on TheFriend and keep a straight face if you can.
Continue on TheFriendMeet Defne: open Defne's profile on TheFriend.