If you only want the tiddler's content and don't mind it appearing as the body of your email you could have a look at Riz's Social networking plugin here:
It works for Gmail, I don't know about Outlook.
I had a few hiccups getting it to work but it does work for me. It requires 4 tids from Riz's site:
Animate, svg icons, macro and stylesheet.
I edited the macro, adding ampersand (&) before subject in mailto based on this info;
https://stackoverflow.com/questions/2583928/prefilling-gmail-compose-screen-with-html-textt
Drag and drop I don't know. Good luck.