Slicing Pie means paying the people who help you with equity in your business instead of cash. This can be a very powerful tool that in some ways is better than cash (but not all ways, unfortunately).
Slice the pie properly and you will compensate the people who help you in a fair and equitable manner. Slice the pie improperly and you will destroy your business and burn bridges with the very people who came to help.
Tread carefully, buy the book and enjoy!