How To Hit Your Brother
First, an important announcement: I apologize to my little sister for all the times I hit you when Mom wasn't looking.
Hitting your brother is an enterprise not to be entered into unadvisedly or lightly, but carefully, discreetly, quietly, and with a close watch on your mother. It may appear at first glance to be an activity born of the heat of the moment, but a successful clobbering requires planning.
First, choose your time and place. It should be within your mother's earshot, but not her line of vision. Your mom should be busy, but not so busy that she doesn't notice the set-up, which will be important later when you're presenting your defense. Don't do it when she's on the phone -- she's likely to tell him, "Fine, hit her back, just do it in another room." Ideally, she should be engaged in something that keeps her in one place and requires a certain amount of focus, such as writing a letter or paying bills.
Next, the set-up. It is important that you come across as the victim in this situation, even though yes, you are technically on the offense. This is one of the most delicate stages of the process, since you need your mom to be subconsciously aware of the recent history of injustice, but not aware enough to make a preemptive strike and separate you. A few trial efforts will help you refine the volume and pitch of your complaints so that they stay just beneath her conscious attention. Phrases such as "I'm trying to help you" and "Use your words" will establish you as the reasonable party in the coming dispute, and may be used to your advantage later.
Now, move on to the escalation phase. Stay in control, as this is the point at which a flare of emotion can completely blow the operation. Raise the pitch of your voice but not (this is crucial) the volume. As counterintuitive as this seems, you need to keep the volume of the interactions at a constant level in order to keep your mother from intervening. If the altercation becomes loud enough to break her train of thought, you'll have to fall back and wait for another opportunity, perhaps hours later. Instead, step up the emotional intensity and the frequency of your comments. Now is a good time to introduce more action-oriented phrases such as "You already took three turns!" and "I'm already sitting here, don't push!"
So far your efforts have been primarily verbal, but toward the end of the escalation phase you may add the physical component. It is essential that you do not, no matter how tempting, hit your brother at this point. He needs to formally start the physical hostilities, and this must be managed carefully. Instead, get into his personal space without actually touching him. Wait until he puts down a toy, and grab it immediately. Without making physical contact, lean close to him and hang your arms on either side of him so he is essentially surrounded. The final never-fail technique is to sit in front of him (preferably in the middle of his current play activity), stretch your mouth out in a dreadful grimace, stick your neck out so that your faces are inches apart, and make a silent "grrrr" motion toward him.
A certain amount of sacrifice is required for a successful whomping of your brother, and this is where you'll have to take a deep breath and take one for the cause. He will inevitably take a swing at you. You need to duck, but not completely. He MUST make contact with your body, but since you're expecting the strike, you can make the impact minimal by using fast evasive maneuvers.
Finally, the moment you've been waiting for -- give him a good smack, and enjoy it. You've earned it! Personal tastes differ greatly as to approach and style, but give it all you've got. Wow, that felt good, didn't it?!
Don't get lost in the victory, though -- you're not done yet. Perfect timing is essential at this point. After you've hit him but before he really gets wailing, yell at the top of your lungs, "Mo-o-o-o-ommm! He hit me!" This establishes him as the aggressor, and it has the additional merit of being perfectly true.
The next few minutes will require careful responses to the inevitable cross-examination by your mother, and the variables at this stage are too numerous to cover in depth. Remember, though, you are the victim here. This is the time to turn on the waterworks, display any bruises you've acquired in the last week, and present your aggrieved defense to the judge. Later, when he's in the corner having a time-out and Mom is balancing the checkbook again, you can dance around and make faces at him, your objective reached and your adversary defeated.
On second thought, maybe I should reword that important announcement:
Sorry, Mom. I promise I won't do it again.