Bad internet. A combination of internetz and nigga, which is black people slang variation for the white people slang term 'nigger'. The nigga part is reference to the stereotype of things by black people being bad i.e. crack
When one ejaculates into the anal cavity of someone who is of African descent or heritage.
Archibald: Bro I had the craziest sex last night!
Pubert: What did you do?
Archibald: Well first I gave her an alaskan pipeline then I gave her a nigganutbutt.