For me, that is where the serpent lies (dwells). The serpent is the carnality of this realm. As I feed it, it consumes me. Like an addiction. You take it because you like the affects, but the more you take it, the greater a hold it has on you, to the point that it is all you think about, it's all you live for and you find yourself trying to get away from in instead of running to it, but by then, it's too late. The only thing that can break you free is an intervention of God . . .which is what he was waiting for all along.
Dust is the serpents meat. Knowing that snakes don't eat dirt, I think it's pretty safe to say that this is more about type and shadow than literal. But hey, as far as I'm concerned, the literal applications are the least affective in our spiritual lives anyway. Scripture states that "we" are made of dust, we are walking dust, and we'll return to dust when we're done walking. So, the serpent is carnality in this realm. My nature is it's main diet. The more I feed it my nature, the more "it's" nature manifests in me.
We are what we eat. The church has taken spiritual truths, blended them with natural reasoning and logic, birthed religions filled with rules, regulations, boundaries and bondages, and called it God's house. We elevate our beliefs to such a level that no other person can approach us without first honoring our belief system. If they don't accept our positions, to hell with them. And all the while, God is just setting back, knowing full well that carnal wisdom can not support spiritual truth. Eventually, our belief system will implode upon itself and when it does, death comes to self and freedom resurrects from the rubble within me.
There is a purpose for the lake of fire, it's to purge and cleanse ME from MY carnality. Your interpretation of the Word is not for you to apply to me, and my interpretation is not for me to apply to you. If we'd stop trying to make everything fit literally and recieve it all in it's entirety inwardly, there would be much less bickering and much more uniting.
but again . . .that's just me.