In the purest form, and this is ridiculously tied to the limit of 5 episodes per week, you could set a do-more slope of 30 per week, and record up to 5 points for every day that you didn’t watch anything.
i.e. 5 points for no episodes, 4 points for one episode, down to 0 points for five episodes, and negative points for a full-on binge.
The beauty (or horror) of Beeminder is that if you manage to go longer without watching anything, your binge-budget gets bigger…