How can I fuck-proof my bed so that my roommate doesn't fuck on it while I'm away for a few weeks?

First off, my bed is super comfortable and totally fuck on-able. My roommate on the other hand sleeps on the floor and might be tempted to do some of his lady friends on my bed while I'm away for a couple weeks. This is something I'd like to keep from happening since my bed is so comfortable and awesome. And fwiw our bedroom doors aren't equipped with any locks.. Any thoughts??