I hate how my normal, boring and undecorated pen looks. So, then I tried this neat little trick.
I'm using a sticky note and I suggest you trim it to size so it will actually fit in the pen tunnel thing.
Take apart your pen. The spring and everything. As long as you know how everything fits together, this should be easy. If not, ask a pen technician. (Is there actually such thing?)
Using a sticky note is useful because you can just stick it on like shown.
You should know how to assemble a pen. So just wrap in the loose ends of the paper and stick it back together!