What's flatline exactly?

I think it's like this: Imagine a graphical measurement over time. When it doesn't change for a while, then you see a "flatline" (a flat line). Which means no change in sexual desire nor interest. Additionally it probably means very low or no desire/interest, which is what I experience sometimes. But it's not really zero for me.

I think this all means that after some chaser effects, if you stay strong, then there's the flatline, and probably low urge in general.