When do you check your cm?

Have you done it after you poop?

I read that's a good time to check it sooo I did and it was red gooey and thick kinda like mucus, yesterday it was thick just not red,I haven't had a period for two months now and taken a test both negative which is extremely disappointing.

Could this be my new period possibly?

Why do they say it's good to check your cm if some people say cm really don't matter..