The trembling catches Sizhui's attention and, while he doesn't have much time in-between, he does manage drawing up quickly enough to keep just the head and a few inches of Itto's cock in his mouth before he stiffens. Which is good timing since he's coming a couple seconds later, shooting down his throat and flooding his mouth so full, it's a miracle Sizhui can keep most of it in, but he swallows whatever possible then Itto's dick pushes further into his mouth.

It's an unexpected motion that causes saliva and cum to trickle from the corners of his mouth, yet he applies suction as he withdraws, lifting off with a soft wet pop, then his left hand raises to catch any stray strands of fluids and the right strokes over Itto's cock, spreading the remaining mess along his length. He hums approvingly, clearly satisfied, if the mindless pleasured expression on his face is indicative at all. Had any too-curious passengers heard Itto moan like that? Perhaps... but does he care? No, not in the slightest, he's far too delighted by his partner having orgasmed (and more focused on what else he has planned).

But he does have sense enough to first remark, “There's a good boy,” then he pats Itto's thigh and gingerly scoots up along his chest. “Here, let me get up, that way I can sit on the seat and you'll be able to kneel on the ground between my legs.” No other clarification at the moment, just Sizhui shifting further down, his ass grinding against Itto's lap on the way before he hops up onto his feet, those pretty white robes falling neatly around his legs and covering him up quite nicely from anyone who might've been peeking.