hahaha. Funny post. Well, a few things to be said about this topic. First, you have to keep in mind that a large part of how we look is genetically determined. In other words, if we have big biceps before we start weight training, then unless we do something awfully strange, we're going to have even bigger biceps when we are done. If we have tiny calves, then likely they will always be on the smaller side.
The thing is, if you bulk up, then every part of your body will bulk to some degree. And, when you cut, then every area will cut down. Over the long haul, you CAN train certain areas for mass and grow them MORE than other areas... but, that takes years to see a significant difference. Secondly, it's difficult to tell what you mean by "under arms". If you are talking about the triceps, then you wouldn't work your triceps as much. If you're talking about the lats, then you would train them less.
But, here's the thing. Most experts and people with experience would tell you to train every group equally. It's not recommended to offset the balance of your own musculature by doing some exercises lots and others very little. I know that's not what you want to hear, but trust me when I say that it truly is genetically determined.
The best recommendation I could give you is to train every part of your body, and keep strict tabs on what you eat and how much you eat. By controlling your diet (eating the right amount of calories and very healthy foods) you will be able to burn more fat, while building strength and hopefully chisel out your body to the lean look you want. Do that, and you'll be a step ahead of most!