Pull with weights
What materials will I need? For weights, you can use anything: barbell weights, lead tire weights in a small stuff sack, a plastic jug with water, etc., etc. If you can make it small enough, you can wear shorts and hang penis and weight over the edge of your computer chair as you work.
How much weight? Start with 2-3 pounds (1-1.5 kg). Each week, add weight in 1/2 pound (.25 kg) increments, or more if comfortable. Work up to ten pounds (4.5 kg) or more.
How long? Hang weight for 10 minutes, then remove for 10 minutes. You can increase this time later, but always monitor carefully. Remember to remove weights regularly!
How often? I hung weights for one full hour (takes a total of two hours with breaks) morning and afternoon, every day.
What else? Do PC exercises every few minutes while hanging to encourage circulation. Stop immediately if you experience pain, excessive coldness, numbness or discoloration.
Pull around your waist
This is awkward to put on and remove, but as long as somebody's trying to sell it for DM 298 (~$US 160)(www.penisplus.com.), you might as well know about it.
You can also do it with just an Ace bandage: In either case, you need to tie a taut line hitch - a knot that will serve you in many other ways (great for tying down loads on cars, for example). Here's a diagram(thank you, Boy Scouts!):
Pull with your leg or foot
You can wear this while walking, or tie it to a fixed object for use while sitting at the computer (wearing shorts or bathrobe makes this easier). You can also make a loop for your foot, and vary the stretch while your work at your desk or watch TV.