addthis: custom message when sharing on email

Question

I am using addthis on my site to share links to different platforms. I use open graph and twitter card for giving url, title etc when sharing on facebook or twitter. But when sharing with gmail or any other email I want to have my custom message on body of the mail. Currently I only have title in Subject of mail and URL in body of mail. Please guide

<div class="addthis_toolbox displayNone" addthis:title="test title" addthis:description="test description" addthis:url="test URL" >
    <a class="addthis_button_more" href="javascript:void(0);"></a>
</div>

Thanks