Shen Yuan has every reason to be skittish and scared of Bingge's temper. Maybe not Airplane's flavor of skittish but. He is Not A Pretty Sister To Be Banged. (As far as he perceives for a good while at least.) Therefore there is ALWAYS a risk of becoming cannon fodder.
He is still stubborn af. Sticky. And devoted.
Bingge definitely is lashing out here and there from the start. He just wants this pest to go away. When he's calm enough he reasons that The Pest is not harmful, not threatening, no worse than a persistent annoyance who keeps refusing to do anything Too Offensive, and therefore he Can't Just Kill Him. Would be rude.
But when his frustration mounts too high, edges are too rough, grinding. When Shen Yuan is grabbing him, stopping him, only because he spotted a hazard but he can't communicate that fast enough to preempt the reaction... Bingge snaps. Smacks. Swats away. Hits. Claws out. Kicks.
Shen Yuan hits the ground. Bleeds. Maybe apologizes, maybe sputters out an explanation about what he was pulling Binghe away from.
He never stops pressing to remain Binghe's Disciple. To learn.
He never stops trying to warn Bingge about dangers he spots first, even when it nearly always gets him at least bruised– from his arm being grabbed too hard for daring to grab a twitchy half heavenly demon too abruptly.
There's no way Bingge doesn't notice, even if he is mostly bewildered.
If he is holding to the personal guidelines that demand he repay kindness with kindness, harm with harm, and forbid him from being TOO awful to someone who is being entirely neutral and even Positive to him...
At least some of the time, from the start, he notices he had hurt Shen Yuan for no apparent valid reason and it Bothers Him. Especially if it keeps happening. Shen Yuan insisting its fine, playing it down, would only help so long. Binghe is the one with enhanced senses. Who can smell the blood. Who might be able to tell there are hidden injuries if he checks SYs qi.
Shen Yuan is So Weird! What is this persistence? This insistent assistance? This person who scolds him for carelessly walking into range of flowers or animals that could be harmful without even looking, complete with descriptions of some of what the hazard was. And yet flinches from his temper, tries to bow "filial-ly" when Binghe seems angrier, shrinks away for a while.
Has Binghe ever had reason to properly consider aphrodisiac-poisoning being handled by a pair of men? Does he have the SLIGHTEST idea what that requires/entails?
Because we don't really have much to indicate Bingge didn't learn women entirely via experience and instinct. And if he's never had someone Instructive enough about men...
Bingge hasn't been This Bad At Sex since his first forays. He is trying to help! What's wrong? Uh... hurry up and feed him some of your blood, "shizun", so you can fix what you just broke. Better see if it helps with this kind of aphrodisiac while you are at it because Clearly this isn't working...