In addition to Vicky_Molokh's answer;
Heavenly Guardian Defence (Exalted p.193) perfectly parries "any attack" and where most charms specify they only work on attacks directed at the Solar, this one does not.
Since you are playing an Eclipse caste you can learn charms of other exalts, Lunars have several charms that interact with the Defend-Other action that may interest you:
Mother Grizzly Attitude (Errata P.54), This is exactly what you are looking for, "While the Lunar is protecting a character with a Defend Other action, he may use this Charm to prevent any attackers from targeting the warded character even if they overcome the Lunar’s interposed DV with their attack roll, forcing them to instead direct their attacks against the Lunar for the duration." 1st charm off of a Stamina Excellency.
Ferocious Guardian Beast Stance (Glories: Luna p.23) a perfect defence that can only be used on the behalf of someone you are defending. 2rd charm off a Dexterity Excellency.
Lunar Hero Style (Lunars p.194) has some charms deep in the tree (5th Charm) that may interest you as well, particularly Den Mother Method and Running Through the Herd.