Ever wondered how the first cousin/second cousin "thing" works? Well, here goes.....
The child of your parents sibling is your first cousin.
That cousin's child is your first cousin once removed and you are his. Think of the "once removed" as one generation removed.
Your cousin's grandchild is your first cousin twice removed, and so on.
Your child and your cousin's child are second cousins.
Another way to look at it: First cousins share a grandparent. Second cousins share a great-grandparent, and so on.
Or you can just call them all cousins and be done with it!