Step 1: First things first, you need a stamp.
Have you ever wanted to make your own?
Well, it's pretty easy to order a stamp. I ordered mine from iPrint.com (Trodat printy 4911 with a font size of 8).
This particular stamp has a window in front so that you can see where your stamp will fall but for a single line of text in the middle of the stamper, it is a little tricky to place it exactly where you want it.
Step 2: Tape
The first step is to get two pieces of tape. Any tape will do but I used scotch tape.
One piece will need to be longer than the width of the stamper assembly. The other piece needs to be the width of the inner cavity of the stamper (the shaft that the stamper travels).
Step 3: Stick the tape.
Step 4: Test Stamp
After you have a good stamp, peel the tape back off being careful not to smudge the fresh stamp.
The ink wont dry on the tape so watch your fingers.