Ok, I did this one yesterday at the PEP1 event while working up at Allerton Abbey. I was working alone so I couldn't get pictures of myself doing the stuff. Plus there was muddy cob all over me so I didn't want to dirty up my phone.
Low Grade Cob is just dirt and water. No straw and no additional clay slip. Or at least the dirt here has enough clay for it to work. I sifted the dirt through a 1/2" hardware cloth sifter and mixed it in a bucket with a small amount of water.
Normally this BB would be easy, slapping cob up in the gaps/chinks of a log wall as you build a wofati. In this case, the wofati was already built and the cob had to squeeze between log gaps and/or through 1" holes to get to the other side of the wall. I make a plunger tool that kind of helped. Anyone else doing this under "normal" conditions will probably get the job done in 1/3rd the time since access will be much better. I also used a big pastry bag to squirt the cob into gaps. I made it extra soupy so it could be plunged/pastried into place. (Hint) If anyone else is doing this same job at the abbey, sift your soil down to 1/4" or smaller so the pebbles don't plug up your applicator(s).
I did about 22' of linear cob on this project. I photoshopped red lines on each log above where the cob was applied so you can see where it worked. I skipped the middle of the wall since there's a big post on the dirt side of the wall that creates a huge void. Filling that will probably take a 2-3" hole at the top and a couple wheelbarrow loads of sloppy cob and a funnel contraption.
"Hundreds of years from now it will not matter what my bank account was, the sort of house I lived in or the type of car I drove... But the world may be different because I did something so bafflingly crazy that it becomes a tourist destination"
I updated the requirements a bit. We happen to have a spot that produces what we call "shitty cob" - a near perfect mix of sharp sand and clay. With a little water it makes a low grade cob. That is what you were using.