The burrowing succeeds in breaking Shirogane's concentration. Partly because a cat that size attempting to burrow under the crook of your arm so it could put its head on your leg usually dislodge whatever was already on your legs in the first place.

In this case, it was his computer. Shirogane manages to catch it, arms raised and giving Aria-shachou ample space to plop his head onto Shirogane's leg like a large and very blank-looking bun. He gives Akari a sigh, "I can't work like this."