A son you are the father of because you had sex with your wife's sister, she got pregnant and you produced a child together. (Your sister-in-law's OTHER sons would be your nephews)
My sonphew is always arguing with his little sister over the television.
When your son is the sister of your wife's son, because you had sex with her sister and she also had your your child (your son)
My sonphew and his sister are constantly fighting over what to watch on tv.
When your child is your daughter AND your neice, because you had sex with your wife's sister and had a daughter.
I have 2 sons a daughter and a deice.
When your child is your daughter AND your neice, because you had sex with your wife's sister and had a daughter.
I have 2 sons a daughter and a deice.