It used to be “closed mouth, strained and uncomfortable” until my friends and I started a tradition: we exchange pictures almost daily, within our closed group. Someone posts the daily rule (“a picture of you relaxing/with a loved one/eating ice cream/in nature”), whoever responds first gets to pick the next day’s. It’s especially helpful right now, just a daily dose of fun and a way to stay connected.
The pictures aren’t shared with anyone outside of our group, so they don’t need to be anything special. Because it’s such low stakes and I’m actually having fun, I learned to smile naturally. My mouth is usually slightly open, and my eyes are smiling, too. It’s a big relief. I no longer hide from cameras.