Evidently, despite his lack of experience, Itto's enjoying sucking him off. It's clear in his meticulous, rhythmic motions, the way he uses his tongue to make Sizhui squirm harder and moan, his pitch growing higher with every lavishing motion. Keeping his head rested back on the seat allows Sizhui to stare upward through the train window, watching the billowy clouds drift by, which proves more difficult each passing second as his eyes become heavier. Through his lashes, he's able to still make out shapes, but he can't resist squeezing his eyes shut entirely once Itto changes tactics.

Both his hands reach for Itto's horns and hang on, his lower-half instinctively arching toward that forked tongue, although he's quick to catch himself, and while he doesn't withdraw, he does hold steady. Not that this matters after Itto completely engulfs him all of a sudden, causing Sizhui's eyes to snap open, a low, long-drawn-out guttural-sounding noise escaping before it can be stopped. “Oh Gods, Itto—” then he cuts off, sinking his teeth into his cheek to muffle an actual yelp, fingers cinching tighter. Hopefully, Itto will be alright being held down for a couple seconds because it's what happens when Sizhui fleetingly loses himself in the pleasure. As soon as he realizes this, he does let up, murmuring soft, mostly incoherent apologies while moving his right hand to pet Itto's hair again. “You... you're doing so well,” he manages, ardent regardless of breathlessness.