I've run across the expression/word a few times in manga, and generally the context indicates that it's a conjugation of する with the ～がる indication of "3rd party appearance of internal state" (as in 怖い -> 怖がる). Is this generally correct? If so, where the や comes from? or is this just yet another 'special' conjugation?
An example fragment I have here is:
(Context is a few moments before a love declaration... meaning is obvious enough)
Another example comes from pg 12 of the first QED manga, where an enraged player who has just lost a video game competition yells: