I don't think I like it but will someone explain Neto what was it again?, to me?
I always forget a bit about it, but as long as it's kind of a choice i don't mind I suppose.
Netorare is when Persona A "steals" (or at least has sex with) the love interest of Person B, without the consent of B and from their perspective. The love interest generally doesn't consent either, because if they do, it's usually considered cheating instead of NTR, but they are sometimes used interchangeably. Netoru is the same thing, but from the perspective of Person A.
To pull examples from the description and images, netorare would be the image of Linda (a love interest of Kate) sucking Chris' dick, and netoru would be "stealing your brother's girlfriend."