First cousins once removed.
First Cousin, twice removed.
The children of your wife's first cousin are her first cousins, once removed. They are not related to you.
Your daughter is first cousin once removed to your cousin. Your daughter is second cousin to your cousin's children. Your cousin's children are first cousins once removed to you
First cousins once removed.
Your cousin's children are your second cousins
Your children and your first cousin's children are second cousins.
They would be your second cousin.
If you are first cousins, they would be a first cousin once removed.
The children of your grandmother's first cousin are your second cousins, once removed.
You and the children of your first cousin are first cousins, once removed, to each other. Your children and the children of your first cousin are second cousins to each other.
The relationship between your sister's (or brother's) child and your cousin is the same as the relationship between your child and your cousin. Your child and your first cousin are first cousins, once removed. Your child and your second cousin are second cousins, once removed, and so forth.
Your children and your first cousin's children are second cousins.