Parafilm is a wax film you can use to seal things with in the lab, sort of like an alternative to saran wrap. It stretches if you pull it gently as you wrap it around something.
You remove it from the rool by cutting with scissors. You can seal a stack of 3-4 normal sized plates with a full width strip of parafilm if you're careful.
If you need more, there should be some on the racks next to the -20C fridge #5, or in the stockroom. If you're not sure, ask the dissectors.
P/N: Parafilm PM-996