Dude everyone gets ''amoged'' from time to time.
But this is quite a case you've got there, you don't seem to be able to command respect, otherwise this **** wouldn't go THAT far.
You're just not strong enough, with your mind.
Still, there are 2 ways to make him stop:
1. Killer instinct= stop OR I WILL beat the **** out of you.
But I don't think that it will work for you, people who are capable of doing it don't start a thread in a forum asking for advice on this subject.
You seem to lack this killer instinct, obtaining it will take alot of time and a big change, it's up to you.
When you have it, chances are people will ALMOST NEVER try to **** with you, only when you **** up and give them a reason, even then not as extrem as your case.
Here's is waht you do, but it will ONLY WORK when you have 100% confidence and what I call killer instinct, I don't mean looking ''mean'', rather the look you gain by going through alot of ****.
Doesn't matter when, even while having class (did that ****, earns respect, not that important to me, but probaly to you).
Stand in front of him and tell him that you WILL beat him up, if he makes fun of you again do NOT lose your focus, keep cool and proceed.
If you react or feel intimitated, then you've allready lost.
Man you're a big guy, use your friggin body it has other uses then working and ****ing ya know?
2.Being more witty then him, tourning the table around in YOUR favor, making the class laugh about him instead of you.
I just freestyle **** out of my head instantly and I am very good at it, I can top most of the **** that comes at me.
All this your mother blablabla **** is for KIDS, NO REAL MAN says this bull****, stop it.
This guy has probaly things that make him weird too, a weakness.
Find it.
Know your enemy and know yourself, then you'll never lose.