:
Numeric codes in adult content follow standard patterns: %E3%81%97%E3%82%8D%E3%83%8F%E3%83%A1 4017-214
In this case, "しろハメ" likely refers to a specific used by a JAV production company or a content archive. Several minor studios use "Shirohame" as a series prefix. : Numeric codes in adult content follow standard