"I'm in real trouble now!"
This Quirk is a tad odd in that it only activates when Isamu is in a situation that he recognizes as being "dangerous"; or at least thinks poses some threat to his person. When this occurs, his brain generates a unique type of electrical signal that transmits not only through his brain but also between his limbs and throughout his body. As a result, his reaction time increases drastically; he can think through and respond to a situation faster than he can usually, allowing him to come up quick solutions or "escape routes" from the current predicament. Furthermore, the electricity now coursing through his body in this state increases his physical stats by no small amount: he can move faster, hit harder, and take more hits. While it isn't close to enough to match someone possessing a Quirk that focuses specifically on any one of these areas, the well-rounded nature of the power up can prove invaluable and his faster thought process allows him to come up with tactics to help bridge the gap. It cannot be considered a completely combat-based Quirk in its base state, though it can be used to enhance and supplement its user's actual combat prowess. Shinra Wakatsuki explains that Pinch's power comes from what can arise from it, rather than the base power itself.
In that vein, through extensive use of his Quirk, Isamu also discovers a few other aspects of it. As his skill with it increases he gains a greater amount of control over the electricity going through his body, becoming able to focus it on one limb or organ. The increased effectiveness that would spread throughout his body now becomes focused on that area in particular, buffing it tenfold. If he stores up enough of the electricity in the one area before attacking or performing some other action with it, Isamu can even discharge an amount of it to bolster the action further. When used in this fashion Pinch becomes much more combat-oriented, as the attacks Isamu can land have much more oomph to them than in its normal usage. However, it comes with the downside of leaving the rest of his body completely normal, if not weaker depending on the amount of electricity used; if an attack misses he will be incredibly vulnerable and be dealt greater damage.
After discovering the emission aspect of his Quirk, Isamu also uses it for more miscellaneous purposes, including allowing him to grip and slide along metal objects for faster escapes.