Look at its vein (did manjuu have vein?), I don't think it's pleading/begging for mercy though. Instead, I'm pretty sure she's saying something stupid, like "This is Marisa's place because Marisa's already doing home declaration noze", "Marisa is saying sorry noze, mister human must forgive Marisa noze", "This is all Reimu idea, Marisa is just a victim, punish that shitty Reimu not innocent Marisa noze", bla bla bla.