For the entirety of Sarge's speech, Rodeo's face remains completely impassive. The amused smirk melts away, but it isn't visibly replaced by anything at all. His eyes are unreadable, his face entirely neutral as he listens.
Which is, frankly, never a good sign.
Because Rodeo always thinks something about everything. And when Sarge gets to the end, declares that he likes his sister, Rodeo shows him exactly what he thinks of that. Without warning, without a goddamn second of hesitation, his fist cuts through the air and smashes into Sarge's mouth with crushing force. It's lucky for him he's so damn tall (and unlucky for Sarge,) because even though his friend is reclined on his top bunk, Rodeo can still get good enough leverage to deliver a catastrophic hit. He doesn't stop at one punch, though. He grapples for Sarge's shirt, knotting the collar in his fist and yanking hard, trying to drag him forcibly off the bed.
"You fuckin' scumbag piece of shit, you fuckin'-- fuck you, fuck you--" Rodeo is snarling as he yanks on Sarge, as the inmates mulling about all stop to watch, as the COs pretend not to notice. Even as he tries his damnedest to drag Sarge off his bunk with one hand, the other fist can't stop hitting, pounding into his ribs, stomach, arms, anywhere it can find a place to land. "My sister?! My fucking sister, are you serious? I'll kill you, I'll fucking kill you--"