The wards feature blood magic, that's why Billy fainted when he teleported in. He was laid up on my couch for hours. [ By his tone, it was hilarious. After the intense concern, of course. ] If you want a key I can have one made, but I'll need some of your blood to work into the enchantment so you can pass the threshold without immediately wanting to kiss your previous meal if I'm not with you when you visit.