The first deer I ever killed, an older friend showed me this technique. I did not ever do it again.
You gut the deer and wipe it out/drain as good as you can. Then you just make a slit in the hind leg skin between the big achilles tendon and the leg bone. Then stick the front hooves through these slits. Put it on like a backpack.
We had two deer. I put mine on with the butt up, and the tail laid over my head, which got some laughs. I think neck up might be more dignified.
We were wearing Helly Hansen rubber raingear so the dripping blood was not so much an issue, otherwise you would be pretty messy.
It is not all that comfortable either, the deer legs are bony and rub you a lot, the ribcage pokes into your back.
It is also scary to have this big furry thing on your back walking through the woods in hunting season; I stopped and put my white T shirt on the deer for fear I would get shot, and we made a lot of noise talking as we walked out.
Now I do like Zbear claw, but I use game bags, and a garbage bag liner to protect the pack. I get the game bags out of the garbage bag as soon as I get to where I am going, and hang them up.