Replying to Help: how to get scumbag off my bed

So my roommate is cool, but he has this scummy ass friend who I swear only showers once a week. Whenever I walk into my room this kid is always on my bed, and sometimes he even gets under my blankets.

What can I do to get this kid to not be in or on my bed...like putting something in my bed or something like that. Need creative ideas

Asking him doesn't work I've told him multiple times to not be in my bed....it's the top bunk too...

Thanks