Couphew
The male child of your bruncle or aunster. Your bruncle/aunster is the result of one of your parents having a child with any of your grandparents, and the son of your bruncle or aunster would be your couphew; your brother or sister's son is your nephew, and your aunt or uncle's son is your son, making the end result your couphew.
My couphews Tommy and Dylan are so adorable when they swing on the swingset, my bruncle Stewart must be so proud of his two sons.