Slide smashing, also known as smash dashing or hyphen smashing, is a simple, yet useful technique. To do it, one must simply dash and use an up smash; the player's character will slide to a stop while performing their up smash. All characters can slide smash, though characters with low traction and/or high ground speed will cover a larger distance.
The most obvious use for the slide smash is as an alternative to using the character's dash attack, which is generally mediocre to weak in terms of power; many dash attacks also leave the character vulnerable to punishing (such as shield grabbing), whereas the slide smash is generally more difficult to punish, and up smashes are usually considerably more powerful than dash attacks. Another use is simply as a method to setup an up smash directly from an approach, which can be used during a combo, as a raw KO technique, or as a mindgame or punish. Characters such as Fox and Pikachu can make great use of this technique, due to their fast speed and useful up smashes.