What are the mechanics fro shoving enemies into a bag of devouring

I was scrolling through the DMG and I came across an item called a bag of devouring. It states that if a creature is placed fully inside of it the bag destroys it and if part of a creature is placed in the bag it must make a Str check or be pulled in. What are the limits for this? Could you put the tip of a dragon or tarrasque tail in the bag and if they fail the check they are pulled in. I believe/heard you can put full-sized humans in a bag of holding so would it be possible to put entire people into the bag thus killing them? I just want to know where the limitations of this item lie.