hash over - Phrases/Idioms
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Also, hash out. Discuss carefully, review, as in Let's hash over these plans again, or The department was hashing out the new syllabus. This idiom uses the verb hash in the sense of “cut into small pieces,” a usage dating from the mid-1700s.