How to add prefix or suffix to post_tag slug?

We can do this by following code:

function custom_tag_rewrite()
{
 add_rewrite_rule("^tag/(.+)-suffix/?$", 'index.php?post_type=post&tag=$matches[1]', 'top');
 flush_rewrite_rules();
}
add_action('init', 'custom_tag_rewrite');

and try open like this http://example.com/tag/post-tag-slug-suffix