Osamu holds his breath for a moment as he considers how he's supposed to respond. It quickly becomes obvious he won't be able to shake Kita off, and with a heavy sigh, he decides he might as well stop hiding it.

He turns away from Kita and tugs his shirt off by the collar, wincing a little as it stretches out his back. When the shirt slides off, a giant bruise is uncovered in the middle right of his back, ugly mottled purple and green surrounded by red skin.

"I fell." He explains simply, barely more than a grunt.