Rolled up sock!

Like you haven't heard this before.
Really, it all just depends on what your priorities are. Me, I don't pack because I'm not full-time, and I have a lot of uhm, very touchy friends to say the least, so I'm paranoid messing around would have it fall out or something. When I'm at home, I just need something that will have some weight and provide some remote shape, so a sock does me just fine. If you want something more realistic, maybe DJs guide would serve better. Those are the only two methods I've heard of anyways, socks and hairgel/condoms, or condoms in condoms if you have the money, but I assume if you had the money you'd just buy a packy anyways.