How to defend myself in court?

It sounds like a simple drunk mistake ( there's your sign) I know how pissed I get when my food gets gone. But your talking a case of the munches. Don't stress get your friend to talk to the other student and replace the food. Now if they still force the issue get your friend to attend the hearing and tell the truth. Then if you had no knowledge of him munching how can you be charged? Now with the time it took you to ask the question and till I answered, you could have already taken care of this. As far as representing yourself Google "Sui Juris" that would help open your eyes.