Sirius would do something like that, it's Sirius Black, total drama queen, how could he not? And McGonagal would've been so happy because finally they were together and she had won the bet against slughorn
or he just stays a stag so she will pet him all the time and becomes her "little friend" and she never knows<<and Sirius is with her one day and it's like "This is what happens when you fallow us one dates!
--------No seriously, you don't understand. I am 24 years old. But you tell me when and where and I'll be first in line with my glasses and my wand. --- this is what I've wanted since the first Potter movie!