You can choose to use browser-length sessions or persistent sessions using the SESSION_EXPIRE_AT_BROWSER_CLOSE setting. This is set to False by default, forcing the session duration to the value stored in the SESSION_COOKIE_AGE setting. If you set SESSION_EXPIRE_AT_BROWSER_CLOSE to True, the session will expire when the user closes the browser, and the SESSION_COOKIE_AGE setting will not have any effect.

You can use the set_expiry() method of request.session to overwrite the duration of the current session.