What is the meaning of this Poem from the Dead Poets Society?

"I close my eyes and this image floats beside me, a sweaty toothed madman with a stare that pounds my brain; his hands reach out and choke me and all the while he is mumbling truth...truth like a blanket that always leaves your feet cold; you push it,stretch it, it will never be enough, kick it, beat it, it will never cover any of us: from the moment we enter crying to the moment we leave dying, it will just cover your face, as you wail and cry and scream"