Yeah, getting stuck on the couch is a very serious 3rd tri symptom!

There is a LOT of increased cm near the end, some if it thin, some of it thick. I can't speak for people who lost their plug in smaller bits (may be what's happening for you), but for me it all came away in one big blob, right on my hand actually! Mine had no blood in it, I got all my bloody show during the second half of my labour, it was everywhere haha!

If you can, (I know how tiring life is at the end), these are the things I did that helped bring in my labour (won't work for everyone, but I went into labour on my due date and my body was ready to go):

-Sex! I made sure we stayed in bed that day and relaxed. About 20 minutes after sex I lost my plug, and 15 mins after that I went into labour

-Lavendar oil in an oil burner and RLT. Helped my contractions ramp up

-Bouncing on my fitball, also helped the contractions ramp up

-Nipple stimulation. Sounds weird but I got DH to, erm, kiss/lick etc. Gave me really strong cramps which turned into contractions

All of those things combined definitely helped me go into labour, my body was ready to go but it sounds like your body might be heading that way too. Good luck!