Regarding your tattoo, I don't know why you want a walrus. I assume that it means something to you. It damn well better mean something to you, because it ain't gonna wash off.
As for the back of the leg, again: why there?
All of that said, I have a tat of a stalking tiger on my shoulder blade. The cat because I like cats, and they mean something to me. The shoulder blade because I can hide it easily enough.
I have four rules regarding tats, that I would suggest anybody follow:
1) No names. Maybe your kid. But not the wife or girlfriend. They change too often.
2) Be stone cold sober when you get it done. It hurts more, but you will be less likely to regret your choices. Also, you won't bleed so much.
3) Below the collar line and inside the body frame, so that the tat can be easily hidden. The leg qualifies. Although tats are becoming main stream, it is very hard to get a professional job with your neck & face all done up.
4) Make damn'd sure the person doing your tat knows their stuff about sanitary work conditions. Hepatitis and HIV/AIDS are only 2 of the nasty bugs you can get from a shared needle or ink. Art work ain't worth dying for.
Also, remember that you will be turning your skin into hamburger. It hurts like all get out. You might also ask your artist what the pain level is for a tat on that part of your body. Different body parts, different pain levels.
Later,
edg