")
[These what you're talking about?":](/tags/artist-colon-mamatwilightsparkle) Because that's the main series I've seen of "Twilight is Spike's Mom" images I've seen.
You could just filter out that artist's tag. IfHowever you don't want to see **any** "Twilight is Spike's Mom" images, but don't want to filter any next-generation "Mama Twilight" images that happen to feature Spike you could do this as a complex filter (remove the quotes): "mama twilight, spike, -next generation".