TS,
Be aware of the fact that while you might want to retaliate immediately, you just might not have the ability to.
I have experienced lower ranks ratcheting up the intensity against me, in response to I guess their perceived "losing" or hell, maybe they think I am being rough. The point is, they can ratchet up the intensity, but they can't just decide to all of a sudden be better than me at grappling. It overall results in a much worse roll for them, because I just 'control' them that much more in response to the escalation.
Along the same lines, keep in mind what you are perceiving as bullying may just be proper use of pressure and control. I train with a black belt who if you didn't know him well you might think is a dick for the sheer amount of pressure he is willing to, and will apply to your jaw in side control. Fact is he is a fantastic, friendly and humble guy who is just practicing good jiu jitsu.
If your bully really is a bully, still refer to my first point. If he is better than you, it is probably unlikely that you will be given the opportunity to retaliate, and if you do, be prepared to get smashed right back and harder than ever.
Sean's post is really on point. You need to become better at grappling than the bully, only the funny thing is, if you did exceed him, you wouldn't need to worry about it anymore.