Ok this involves being at least 51 points into blood (51 point talent) , rune tap (of course) and glyph of rune tap. Vampiric blood helps.
Basically what this exploit will do is make your rune tap heal alot more than usual
1. Gain enough runic power to summon the dancing rune weapon
2. Summon your dancing rune weapon
3. Use vampiric blood if you have it then use rune tap
What this does, since your dancing rune weapon copies everything you do and has every glyph you have, it will also rune tap. However, this is the exploit. Dancing rune weapon will try to heal your group for 10% of its hp, but instead will focus every heal towards you. The amount of healing you get is based on how many group members you have. So if you have a full group of 5, you will get healed for 40% of your hp on top of the healing of normal rune tap. The most healing ive done to myself was about 27.5k hp in a tank set.
Heres a screeny of me in a group of 3 after a cot run (i got my mount)
ImageShack - Image Hosting :: dkhealxk7.jpg
Notes:
Ive tried with army of dead and ghoul out and it doesn't work. Also this will not work solo, you need to have a party.