Artist's commentary
Illya's long-term endurance training
I didn't make it in time for March, but here's Illya's long-term endurance torture. The lotion applied to the dildo has aphrodisiac effect and stamina-recovering components, so Illya-san has her body and mind turn into mush over a long period of time while unable to pass out. (April 3rd, 20:08 - added a version with Illya in ecstasy)
There's a bonus variation on Fanbox.
https://fumihiro.fanbox.cc/