Pistol Kiss is a special, mighty technique of Boa Hancock, also known as the Pirate Empress and a Seven Warlords of the Sea from the One Piece series. The ability is a manifestation of Hancock's powers, the Mero Mero no Mi, which allows her to petrify anybody who gets an attraction for her. Pistol Kiss, or "Pisutoru Kisu" in Japanese, is one of Hancock's ranged attacks in action, mixing her Devil Fruit effect with some fighting.
Hancock does the Pistol Kiss move by blowing a kiss, resulting in a heart-shaped attack that she can shoot at those who are on her radar. Most importantly, throughout its application, this move is seen to work both in close and long-range combat. The heart-shaped bullet that Pistol Kiss gives rise to basically works like a carrier to the powers of petrification that Hancock possesses; anyone shot by this will turn into stone just because of their lust or attraction towards her.
It passes through physical defenses because one of the most interesting things about Pistol Kiss is that it's capable of avoiding classical physical defenses. Unlike usual projectiles, heart-shaped bullets produced by this technique keep the mystical properties of Mero Mero no Mi within, so they become a threat even to those who would normally not be vulnerable to physical attacks. This is another ability that definitely makes Pistol Kiss such a useful fighting tool at Hancock's disposal against her enemies, particularly considering how many could easily dismiss the weapon's potential due to its fanciful appearance.
Visually, the way Pistol Kiss is reproduced throughout this anime is rather beautiful. Typically, whenever Hancock is shown using the skill, she blows her kiss with excessive elegance, and then a glowing, heart-shaped projectile materializes right after. The speed and trajectory of these heart bullets are usually magnified by the animation, showing how deadly they are despite their otherwise innocuous appearance. This sort of visual contrast between the technique's cute aesthetic and its lethality only served to further increase the appeal and memorability of Pistol Kiss.
This attack has been used on a number of landmark battles in the One Piece series. One of the many times it was used was during Hancock's fight with Monkey D. Luffy on Amazon Lily. In their fight, Hancock blasted Luffy with a Pistol Kiss to demonstrate the technique at full offensive capability and what it does when aimed at a tool immune to her allure. This scene didn't only illustrate the power of Pistol Kiss but was a monumental scene in the development of the relationship between Hancock and Luffy, a subplot that has become relatively relevant in the grand scheme of One Piece.
In advanced applications, Hancock can use Pistol Kiss in combination with Armament Haki, which is basically a form of spiritual energy that can be embedded in attacks to heighten their efficacy, or it can be raised to use it as protective defense. These heart-shaped projectiles can be infused with her Armament Haki, which in turn increases the destructive power and effectiveness of the attack against opponents who would otherwise be proved resistant to her abilities through the use of said Devil Fruit. Thus, the combination of powers from the Devil Fruit and Haki is exemplified in Hancock's applied skillful techniques in fighting.
Given the technique's huge popularity with the fans, Pistol Kiss has made it into most of the One Piece video games and merchandise. For instance, in the game "One Py Berry Match W," one can use Hancock's Pistol Kiss as Special Atack. What is more, the amazingly visual side of Pistol Kiss allows many arguments for fan art, and cosplay with its artists who have given a new look to the iconic heart-shaped projectiles.
In the One Piece power scaling, Pistol Kiss has evolved into a really special conjunction between the powers of Devil Fruits and conventional fighting techniques. Surely not as massively ravaging as some other attacks, this potential for completely disabling surprise attacks easily makes it an ability feared in the world of One Piece. Of course, how well that works is dependent on how easily one might be charmed by Hancock, which makes it pretty interesting psychologically for its usage.
Worth noting is the fact that, while Pistol Kiss would tend to be grouped with Hancock's offensive power, at the same time it really becomes a direct reflection of her character and her background. Being the chief of the Kuja tribe, which values both power and beauty, most of Hancock's techniques often combine elements of battle and expressions of femininity. This duality is perhaps best embodied by Pistol Kiss, in that it is both a deadly attack and a flirtatious gesture that totally captures the identity of the "Pirate Empress."