Sorry about the massive images and blurrycam quality.
So, here goes.
Rip off a small piece of sponge. Make sure it is thin enough to fit snugly in the pen.
Wrap the back half of the piece of sponge with tinfoil. Make sure there is a little bit exposed on the front.
Open up that pen of yours and take out the ink cartridge and front cover.
Stick a small piece of tinfoil inside the pen.
Jam your tinfoil'd sponge piece into the pen.
Coat the outside of the pen in tinfoil.
Tape it up! (I used my best stylus for this image)
Step 8: ???
Step 9: PROFIT!!!
Tips: Since the TF's digitizer sucks, you might need to press a bit harder than on your phone or other tablet.