Your cousin's sister is also your cousin.
Your first cousin's children and you children are second cousins.
Your second cousin's children and your children are third cousins.
And so forth.
He is your second cousin once removed. His children are your third cousins.
Your aunt's sister is either your mother or another aunt. Therefore, her children are your cousins. If her sister is your mother, then those children are your siblings. If she is another aunt, then they remain your cousins.
Second cousins.
The children of your mother's first cousins are your second cousins. The children of your mother's second cousins are your third cousins. And so forth.
Children of sisters are first cousins. Grandchildren of sisters are second cousins. Great grandshildren of sisters are third cousins.
your children are allowed to Mary your second cousins.your children are allowed to Mary your second cousins.
Your second cousins.
Your mother's sister's children are your 1st cousins.
Your children and your first cousin's children are second cousins. Your children and your second cousin's children are third cousins. And so forth.
Your son and your nephew are First Cousins. The children of your nephew and the children of your son are Second Cousins to each other.
Your uncle's grandchildren are your first cousins, once removed. They and your grand children are your second cousins, once removed
Cousin once removed.