>>30730321A lot of those things are actually pre-made props, but getting things like the ball-gag and cuffs to look decent takes a while from my very-very-very-very-very-limited experience working with such items. Most of the outfit, I believe, is actually running off of Koi's default outfit system, though.
If I were more of a scumbag, I could definitely just ask the anon who made that if I could snatch the scene card(and Ms. Muuuuu's character card, to "borrow" the outfit for transplanting onto my Ame card), I think.