It is distasteful to think about incestuous relationships.
Rebecca is talking to some people in the Supernatural fandom when one of the fans brings up her favorite paring of the twins dating each other.
Rebecca wants to interact with the fandom.
Rebecca gives the other fan evidence of other relationships in the show that she supports.
Rebecca goes along with this fan reading some fanfiction before voicing her approval of the ship.
Rebecca is thanked by later by the other fans for introducing them to unique parings.
Rebecca finds herself blocked by her other friends for supporting an incest couple.