a completely self-absorbed, unaware "friend" (READ: douche) that you do things for *all the time* that NEVER returns the favor, even in times of crisis, always making the excuse that they're working or busy or just *can't* for whatever reason--always an excuse--ANY time you ask them, no matter what; someone who never returns the many favors you've done for them.
"My Dad just died and I can't find sittage for the funeral tomorrow. Since I've watched your kids for free for the past two days, do you think you can sit mine for a few hours while I go to my Dad's memorial service?"
Non-Reciprocating Tool: "Tomorrow? Oh, no way. Sorry. Gotta work online and stuff. You know. Busy and all. Can't. Maybe next time."