You just take off the cap of the pen, place it or throw it where it is needed, and wait for the smell.
Please don't do anything that could get you potentially in trouble, I can't be held responsible if this gets you in trouble at school or anywhere, the responsibility is yours, so be mindful how you use this.
Step 1: Materials
-A pen (the ones that are hard to take apart, you can only pull the top area off and has a cap)
-Some grated cheese