Slip angle is probably easier to explain over a beer
However, the quick explanation is that when you deform the contact patch the tire (lateral load) will travel in a direction not the same as the direction of travel of wheel input. As counter-intuitive as it seems, you actually WANT to deform the contact patch. Grip will INCREASE as you deviate from a delta of 0 degrees. However, there is a limit for each tire. Could be as little as a couple degrees up to as much as 6, 7, or more depending on the type of tire (i.e., slick vs. DOT-R vs. street). Your goal is to take that slip angle to the limit and NOT cross over. This premise is the very reason why weight transfer is the enemy. The more weight transfer, the more lateral load you generate and thus quickly exceed the slip angle. Once you get a good feel for what the slip angle is for your specific car and setup you can take the car right up to it and then modulate throttle, brake, steering angle, to dance on that line.
**rest of reply edited for discussion over beer
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