This was so absolutely incredible! I love the characterisations and the humour--but your turns of phrase make this more than just a story--it's... I don't even know what to say about it.
"...the word having time enough to imprint itself on Sirius's lips before they kissed a second time..." Fabulous!
Love the list--#15 is rather self-explanatory, I suppose. :)
So very, very well done! I'm tucking this in my memories!