I'm going to fart in 7th grade and blame it on the resident dipshit
What makes you want to blame someone else for your wrong doing?
I don't want to take the blame for it.
That is a mean thing to do. It's wrong to pass the blame for something you did on someone else. Just because you don't like someone you shouldn't embarrass them any further.
But if I blame it on him, everyone is just going to get laugh at him instead of me.
What you are considering is wrong and cruel. It's best that you excuse yourself to the restroom if you feel the need to pass gas. However, you should never try to embarass someone else or blame someone for your own actions.