My early efforts were clumsy. Jumping willy-nilly as high as I could, with no regard for technique, I occasionally felt my finger graze the underside of the rim. Most times I did not. What I did feel early on was a firm self-awareness­ that I was a two-foot jumper (like Spud Webb, Dominique Wilkins, Vince Carter and myriad NBA Slam Dunk champions with whom I have nothing else in common athletically) as opposed to a one-foot jumper (see: Julius Erving, Clyde Drexler, Michael Jordan). This meant that my best shot at dunking would be to elevate like an outside hitter in volleyball—that is, by stepping forward with one foot, quickly planting my trailing foot next to it and then propelling myself upward off both.

slang To be bested by someone in a spectacular fashion and/or in a way that is humiliating to one. In basketball, to "dunk on" a defender is to perform a slam dunk over them, a move often considered humiliating to the defender. Here's the part of the debate where she really got dunked on&he totally destroys her argument! Sit down, son, you just got dunked on.
Perhaps the most popular obstruction-modified dunk is the Dubble-Up. Aptly eponymous of the its pioneer—T-Dub, an American dunker hailing from Minnesota—the Dubble-Up starts with a person standing before the basket, holding the ball above their head. The dunker approaches and leaps as though their groin would soar above just above the head and their legs around the stationary person. Just prior to clearing the person, the dunker will assume control of the ball with one or both hands, guide it under a raised leg, transferring it to the appropriate hand, clearing the ball-holder, raising the ball above the horizontal plane of the rim, and finally guiding it downward through the basket. While the Dubble-Up mimics a between-the-legs dunk, Kenny Dobbs and Justin Darlington have both performed an under-both-legs variant.
Turn on the windmill. As you approach, bring the ball into your abdomen and back, extending your arm behind your body and up in a circular fashion, like a windmill spinning. At the apex of your jump, bring your arm all the way around to throw it down like a boss. Dominique Wilkins, the Dunkmaster General of the 90s, used to blow crowds away with this spectacular dunk.
The simplest method to measure an athlete's vertical jump is to get the athlete to reach up against a flat wall, with a flat surface under his/her feet (such as a gym floor or concrete) and record the highest point he/she can reach flat-footed (the height of this point from the ground is referred to as "standing reach"); fingertips powdered with chalk can facilitate the determination of points touched on the wall. The athlete then makes an effort to jump up with the goal of touching the highest point on the wall that he or she can reach; the athlete can perform these jumps as many times as needed. The height of the highest point the athlete touches is recorded. The difference between this height and the standing reach is the athlete's vertical jump.