lumossolaris:hp3

Ok so I know the INITIAL process of becoming and animagus is ridiculous, like holding a mandrake root in your mouth for a month and stuff but then what after that? How do you ACTUALLY transform every time after that? Is there an incantation? A specific process? Or do you just think, “Right. I’d quite fancy turning into a walrus right about now.” and BAM! You sprout tusks???