Crunchyroll, Funimation, HiDIVE, Netflix, Hulu, Amazon
Those are the 6 legal anime website for america, Amazon slowly falling out of the race because they fail at properly tagging shit (light novels need their own tag so they stop getting taken down for being 'inappropriate for children) and doing a double paywall channel for the anime. FAILURES! >:x
Anyway best way to find out what legal website has the licenses to what:
https://because.moe/
Amazon has season 1 Crunchyroll has Season 4
I did not read the manga o3o
I might use a japanese term for fluffy as a name.. just because =w=
Dude was more like "Dis mah pillow! >:o" wish I got a photo of it. =w=