@ciku-karugi I read that you already got it working (the trash bag, that is), but just in case, here are the settings I used:



The trick to bind the bag is in the last picture; I used a Shape Key on the top edge ring, scaling it down, and then Key Framed it from 0 to 1 on the first 10 frames of the simulation. I also Pinned that edge ring in the Cloth Setting, so it wouldn’t fall down.
One other thing I learned today, is that there is a Shrinking Factor slider under Shape (in 2.80!), which is really helpful in this case!