Ok, I discovered this when I was very horny and in my room. This technique doesn't require any materials, but you need to be able to hang on a door for a while only using your hands(some doors with grooves you may be able to use your feet).
What you do is get a nice, hard erection. Make sure that you are able to rub your cock up and down a door smoothly. you can test this by standing on the ground and moving your penis up and down along the door. If it is sticky or doesn't move, let it's 'air out' by leaving it alone for a couple of seconds. You then bring a chair, provided you have one, to the door you will he humping. Remember, this is in your room, so lock your door and try and use the closet door to hump if you have. This technique can be done anywhere in the house, but your room is safest if your not alone.
You stand on your chair and face the door. Put your hands on top of the door. Note: you might want to have something on your hands(like socks) to stop pain, cause it will hurt on the bare wood). Pull yourself up so that your chin is above the top of the door. Then you hump away. Remember you need a hard cock to do this, otherwise it won't work and you'll tire yourself out. In about 30 sec to a min, you'll start to feel that orgasm. Then you will cum. Let it get on the door, it acts as a lube. When you cum, your arms will be very tired and you will have to let go. This is a very easy way if your a beginner, and you can do this many many times a day. When I found it out, I did it five times a day. Hope this helps. Remember, you need to have good upper body strentgh and a hard cock.