That's the idea behind “try not to cum challenge” videos...
If you want to discover challenge videos with some originality, I suggest you check out the channel, there are a few videos like that 😉
And if you don't like my videos, don't hesitate to take advantage of the diversity of videos on this website. There are plenty of other creators who produce great videos 👍

Not talking about the "try not to cum"

You've got it right, the goal of this JOI is not to cum, and Marin decides how you're going to cum if you pass the challenge.
However, this time she considers that you should have cum on censorship so she refuses to let you cum if you haven't failed.

But she not refuses, she give 10 seconds without denial on 1-2. And i don't understand about "week" - for full immersion need watch only one time an episode in a week, or everyday watch 7 times for a week?

For the end of the challenge, it stops when the metronome stops. It's true that I didn't clearly indicate the end of the challenge.
As for the 10 seconds, it's an opportunity for those who've won to cum, otherwise they'll be denied.
There are 6 episodes planned in total for this series, with a release every week. So, the next episode will be out in a week and, for the best immersion, it's recommended to not jerk off between episodes. This will make the “try not to cum challenge” of the next episode more difficult 👍
Of course, this is not an obligation and you can discover the episodes whenever you like and in any order you like 😉

Now rules are clear, thank you :)