Maija She will eventually wear them 24/7 like me (although with a break for exercise). She also has a history of trying to cheat, and a couple of months back was the tipping point.
i'm sorry, may i ask how old your sister is? is a chastity bra planned for her too?
frankly, I'm a little worried that your father is "escalating" a bit and thinks that just because it works well for you, it will work for her. siblings are different, @Sara2001 could certainly tell you a lot about that.