using ON CREATION with CURRENT_TIMESTAMP

[Rich Bernstein]

I am trying to create a column that gets a timestamp() or DATETIME the field keeps changing when. I did get it to stick with DATE and on row creation date. I have seen a number of posts but mysqlworkbench is not working as advertised.

When I try to modify a column to timestamp and DEFAULT CURRENT_TIMESTAMP I get this error- Operation failed: There was an error while applying the SQL script to the database.
ERROR 1067: Invalid default value for 'last_date_modified'
SQL Statement:
ALTER TABLE `substantiator`.`images2`
CHANGE COLUMN `last_date_modified` `last_date_modified` DATETIME NULL DEFAULT 'CURRENT_TIMESTAMP'.

Is there something else I need to do? I don't see where to set ON CREATION.