Hoshi Asuna - Mother-s Best Friend Vec-641 -kan... Instant

The prefix "VEC" in the catalog number might stand for a publisher's code, like Visual Entertainment Company, but I'm not sure. It's common for adult games to have catalog numbers that start with letters for different series. The number 641 could indicate a specific release in that series. The title "Mother's Best Friend" sounds like a scenario typical in eroge (erotic games), possibly involving familial relationships.