SIRIUS FLIRTING WITH LITERALLY EVERY TEACHER TRYING (and failing) TO GET OUT OF DETENTION
He tried it with Dumbledore once and the man laughed so hard it almost worked, but then McGonagall came around the corner. Sirius brags until his dying day that he once seduced Dumbledore himself.
James never actually believes him until one day Sirius gives Dumbledore this huge dramatic wink and then Dumbledore winks back.
James stands up and walks out of the great hall.