Ugh this happens all the time for me. Ever since my first pikachu plushie and up to my latest axel one.
I just use hotglue to fix them, though any sort of not-stiff glue would work, I guess... I used normal PASTE on my inuyasha one (just like yours I think) and it dried very hard :'D
But it's okay, I didn't care for that plushie anyways.