I usually use water for my DMT hones. Last night I added a bit of soap to the mix, and I really liked the result. Usually honing with just water, the water dissapears rather quickly. With the soap, it halped keep the water on the hone (much as shaving soap keeps the water on your face!), and I was able to get a very nice finish coming off of the DMT6EE.
Give it a try!