The Blue Butt Bit is mentioned in iDate Sam & Freddie when Carly is spraying a plastic butt for an iCarly bit, annoyed after Sam and Freddie keep her up the night before, arguing in her bedroom about whose mom is freakier. During the web cast, they cannot proceed with the sketch because Freddie and Sam bicker over what bit comes first, eventually turning into an argument about who is right and about respecting each other's opinions.
This bit is never fully shown in this episode or any other, and is not mentioned again.