-It's kind of cut-and-dry as far as creativity goes.
-Though good grammar isn't essential for poetry/lyrics, there are bits that really need some clarification (you want to make your point, or state something in some way)
-Slaughtery isn't a word. Unless you're paying homage to the belgian death metal band, which wouldn't make any sense, I suggest you find another word. Or maybe that 'y' just doesn't belong there.
Not to sound mean, but if I were to come across lyrics like "make me cum so I'll feel better" in a song, I'd probably write the whole band off as a joke.
When it comes to metal lyrics, clarity isn't always high priority. Descriptive, well-rounded thoughts work well, though.
Know what you want to say. Just don't come right out and say it.