Email filter - possible to apply?

So: I have a wysiwyg metabox field:

            array(
                'name'  => esc_html__( 'Additional content area', 'foundation' ),
                'id'    => $prefix . 'secondary',
                'type'  => 'wysiwyg'

and I output allowed tags in <?php echo wp_kses( $secondarytext, $allowed_tags); ?>

I need to be able to protect an email in the wysiwyg area, and want to add a filter to obfuscate using the following plugin:

https://wordpress.org/plugins/email-address-encoder/

This is the filter:
If the content supports WordPress filters, register the eae_encode_emails() function to it: add_filter( $tag, 'eae_encode_emails' );

Is this possible - and if so, where to register and wrap the filter?
Any help - most grateful