If you’re ready for this difficult test of focus and willpower and you live in Japan, the Pikachu PC cushion can be ordered through the Premium Bandai website here, priced at 5,616 yen (US$51).
So I can really see the appeal of a soft, supportive PC cushion.
On the other hand, I don’t think I’d actually get any work done with one that looks like Pikachu.
If you happen to live overseas, you can order the cushion from Amazon USA.