It's no coincidence that Scorpius Malfoy looks so much like his "grandad". Shame almost befalls the Malfoy family name when Draco is revealed to be infertile. So up steps Lucius — After all, "The pureblood lineage must continue... at any cost..."
Warnings: adultery, bdsm, bestiality, double penetration, dubious consent, explicit sexual content, incest, ménage-a-trois, slash, squick, violence, voyeurism. Then I ran out of ideas.