You can make a really simple packy by just stuffing a rolled up sock in some tighty whiteys. Or you could buy a fake packy (dick) at a sex toy store. Their not too expensive...or you can make you can make a homeade packy...check this website out
DJ Knows Dick
Materials:
6 condoms- unlubed work best
hair gel- unscented if possible
Nylon Stockings...close to your own skin color if you want
If you can't find unlubricated condoms then regular ones will do, just wash and dry them off before you start.
Directions:
1) Fill one of the condoms with gel until it's about the size you think the penis should be. Remember that most guys at best are only about 4" long when flacid. Tie off the end of the condom and place your newly created penis inside another condom and tie that off too (double bagging helps in case one of the condoms breaks... you don't want hair gel leaking out of your crotch). Do the same thing for each of the "balls". Remember to double bag the condoms. Most guys have one testicle that's a little bigger than the other, so if you can't get yours to be exactly the same size, even better.
2) Once you have all of your components made, tie the ends of the condoms together to make the basic shape or a penis and a set of testicles.
3) Slip that whole thing into the leg of a pair or nylons, and wrap it back over itself a couple times. If you want to get really fancy you can finish it off at the end by twisting the nylons around the tip of the penis to create somewhat of a "head".