More info: https://www.doujinshi.org/book/670582/ Purchased at https://www.suruga-ya.jp/product/detail/ZHOYA29552 Artist Pixiv: https://www.pixiv.net/en/users/24263 Artist Twitter: https://twitter.com/bulllllion Circle's Site: http://bullion.kemono.cc/
No it's not, both spelling work. Try type "Sin" or "Shin" by using Microsoft Japanese IM, both could result in 深. On the other hand, Juuichi's BE and Shin's BE are the only results that could be considered sinful in my opinion.