Well this is what I do.
Assuming your blog currently hosted on ohthisismysite.com,
1. Point/park ohthisismysite.org to ohthisismysite.com using domain pointer/parking in your hosting control panel.
2. Add the following codes in wp-config.php after the $table_prefix line:
$hostname = $_SERVER['SERVER_NAME'];
$hostname = str_replace('www.', '', $hostname);
if ($hostname == 'ohthisismysite.org') {
define('WP_SITEURL', 'https://ohthisismysite.org');
define('WP_HOME', 'https://ohthisismysite.org');
}
3. Have your lunch.
4. Voila!
The code above is when you have installed WP in the public root and your WordPress address and Blog address (in wp-admin/general-options) is set to https://ohthisismysite.com
. If you have something like https://ohthisismysite.com/blog
then, change the value for WP_SITEURL
and/or WP_HOME
appropriately.
This method works perfectly for my site but not for some other people I had introduced it to. So feel free to try and I’d be happy if it work for you.