Touching things, or being touched.
Ability Score(s): Intuition
Usage: Gauging the touch and texture of objects, as well as discerning feelings of being touched. Most of the time, determining if someone has touched you isn't a big deal and doesn't require a check - you can often plainly see or feel their touch. In the case of someone attempting to do so stealthily (or rather, attempting to touch you without you noticing) this check can be employed.
Feeling someone brush against you is only a DC 15 however in a crowd with multiple senses being triggered at once this increases by a +10. In addition, feeling the heat from someone being near you is a DC 50 check instead (increased by +20 if the temperature is already hot).
If someone attempts to touch you without noticing (such as unwanted groping or from someone attempting to pickpocket you) you can make a Touch check against their Pickpocket check, and if you beat their roll you are able to notice them touching you just as or just before they're able to snatch the item away, effectively stopping their attempted stealthy steal and requiring them to do so some other way.
Touch can also be used as an exchange with Search if you're attempting to find hidden objects stashed on someone's person. Frisking someone who is unconscious and who didn't try to hide the item is instead a DC 20