A slave who is not strong enough to work in the fields and must work in the house of the slave owner. They are weaker and have small fingers for house work.
Kyle Rawling has good small fingers for makin pb and js. He is a house nigga
A white nigga is a guy usually white, that is either friends with an African American and is called that or a term for a white wannabe nigga. Could also be used to mention a white guy with a big dick.