Soooooo... Sub4sub Simon×Grace, and dom!Rocky who tells them both what to do to each other and gets off to the sight?
Neither of those men are doms- Grace is a bratty sub and Simon is eager to please/very soft sub😤
And oooh you KNOW Rocky loves it😌 he loves sitting up and telling exactly what his humans can do.
"Uh-uh, Grace no touch," Rocky trills as he watches Grace's head throw back.
"Ngh Rocky, buddy pl-please!" Grace whines, hips rocking as his cock presses flush against Simon's, a lewd slick noise barley audible above the two sets of breathy pants, "i-it's been hours."
"Been one earth hour," Rocky corrects, "Grace so dumb dumb dumb when this needy. Maybe Simon smarter, Simon how long been in eridian, question?"
Simon's breath hitches, a soft mewl as he lifts his head up.
"ℓ a-and IλVVℓ," Simon manages, his tones watery and pitched.
Rocky hums, "good boy Simon."
Simon shudders at the praise.
"Simon can use Grace for relief."
"H-hey!" Grace whines, "what'a 'bout me?"
"Grace need lesson, Grace need remember what Rocky teach Grace. Maybe Simon nice, maybe Rocky let Simon help Grace."
All the while Simon is just too pent up as he grabs Grace's hip, his cock pressing between Grace's thighs. He knows the rules, actual insertion is only a treat if they've both been good.
He starts slow, cock slipping in and out of Grace's thighs, moaning when Grace clenches, creating a tighter hole, squeezing Simon's cock as his head and shaft nudges against Grace's balls with each thrust.
Rocky chirps, mercury slowly dripping out of his abdomen, a thin crack in the membrane as his ovipositor peaks out from the noises of the two men.
Grace's mouth is agape as he feel Simon helplessly rutting between his thighs. He wants to grab his cock, wanting nothing more than to jerk himself off. But, he knows better than to do something without Rocky's permission. So, he takes bliss for each contact he gets with Simon's cock.
Eventually Simon's thrust grow messy, sporadic as his stomach coils.
"M'gonna, gonna-" Simon whines, "pl-please Rocky, can I?"
Rocky sits there, one claw on the underside of his ovipositor.