I started out with socks and I found that I had to try a few different sizes/styles to find one that really fits you. I quickly realized that my first inclination (really thick, long socks that I wear for hiking) were actually too big to be realistic on my frame, but ankle length socks worked well.
I think there's also a tutorial either online or on someone's YouTube channel (I want to say Chase Ross?) about making a packer out of hair gel and a few condoms. It sounds like it could be a fun project, but I don't know that I'd feel secure wearing it out and about just in case it breaks.
As far as positioning, I bought some compression shorts to help hide my hips pre-T, and they all have a pouch in the front for an athletic cup. I would just put the socks in there and move them around/mold them into a good bulge shape. If you're getting a packer that will require a harness, you could also possibly use the socks with a harness depending on the style.