Silent tear . Human shield
Say it, say – you’ll give me your skin…skin…skin
Fold back, crawl inside, your pinned
Like…wet…pile… Peel…now…feel
I wear, a human shield . Through the elements, stay warm
I put you on, crawl inside . Human shield, skin fold back, crawl inside

Seems as though its about making a coat out of someone's skin...yummy :)

If you don't look at it so literally I think it is about his hiding his emotions or true feelings vicariously through someone...if that makes any sense...
Or could be seen as a sick sort of tortured love where he is obsessed with someone to the point of figuratively (maybe literally!) wearing them as a human shield

As strange as it sounds, I think this is a concept album.
Pieces of Queit: A killer's first kill. Near the end of the song the killer feels guilt for his actions. Skincoat: The killer's next kill. In this song the killer realizes he is going insane. Torching Koroviev: The killer's inner thoughts and personality. Under Rotting Sky: The killer's terrible realization that he is completely insane. No Joy: The killer eventually loses all hope and has become a brainless, mindless killing machine no one can stop...

Hmmmm...I take back what I said about Pieces of Quiet. The killer enjoys the action and wishes to do more, which leads into Skincoat...