Yes, you can assign multiple, non-primary domains to your sites. Non-primary domains 301 redirect to the primary domain. You cannot assign multiple primary domains to a site.
Login to MyPressable
First, log in to MyPressable Control Panel and click on the site you wish to add additional domains.
Locate Domain Section
Scroll to the bottom of your dashboard and find the Domains section. Enter your additional domain in the field and click Add.
You can add as many domains as you prefer to point to your site via this method.