Pout = push one's lips or one's bottom lip forward as an expression of petulant annoyance. Like this photo, so basically means do not make this face expression at me.

What is the opposite of pouting?

Opposite of a pouting expression. grin. smile. simper. broad smile.

Is pouting an attitude?

To sulk around (some place); to have a prolonged sullen or gloomy expression, attitude, or demeanor (while in some place). Look, breakups are tough, but you need to stop pouting around the house and go outside or something.