So I remember a while back reading some clips of centar au racehorse Rodimus being down bad for draft horse mangus and I've got idddeeeaaas.
Rodimus being Rodimus is obviously going to go for Mangus's valve the moment he's let out to socialize in the pasture, spike already swinging between his thighs for all to see. He wouldn't try to mount him immediately, Instead giving Magnus his best prance as he does a quick circle around the bot, only moving in with enthusiasm when he's given no cue for dismissal. In fact, Magnus stays very still while Rodimus comes around to his back, only taking a startled step forward when a face is shoved directly into his valve.
With their size difference, Rodimus barely has to lean over to reach Mangus's valve, digging in with a groan like a starved mech at a buffet. Those massive thighs tense and briefly twitch into his sloppy attempts at making out with that fat node, but he isn't bucked off. In fact, as he continues, Magnus begins to lean back into that uncoordinated touch despite himself.
It doesn't take long for Rodimus to pull back, too worked up and struggling to keep himself from flaring and overloading all over the floor. He nearly does when he watches Magnus's valve clench, throbbing node popping out from it's hood in a wink.
He lifts up to mount Magnus, only to scramble as he barely manages to balance his lower chest on the top of Magnus's rump, hooves curled up and braced on each cheek. He only barely manages to keep from tipping as he strains to find that soaked valve, only managing to prod at his mate's repositories.
Finally, with some desperation and precarious balance, he manages to wet his spike tip on the entrance of Magnus's valve, only making his rutting more desperate. Magnus bucks into the touch himself, tensing down into the touch just enough for the tip to slip in. Rodimus squeals.
His subsequent thrusts only served to immediately throw him off balance and he slips out as he stumbles and barely manages to not fall on his side. He takes no longer than a moment to recover from this though and is mounting Magnus's again before he can even turn to look. In his excitement though, he immediately misses his mark and pins his spike under the mech's repositories instead.
With all the lubricant covering them from the previous mount though, Rodimus seems to pay it no mind, bucking forward and bumping his spike into the underside of Magnus's slowly emerging one. He wastes no time in thrusting to his heart's content, creating delicious, wet friction that is quick to have the larger spike at full mast and leaking.
Magnus's pants and shakily concealed groans are easily drowned out my Rodimus's high pitched moans. Every thrust makes his hips twitch forward, spike bouncing up to smack his underbelly, and his valve throb with need. He only leaks more, this time from his spike aswell, which only adds a nice slide to each smack against his underbelly.
It's when Magnus finally starts to loose control of his voice box when Rodimus flares, transfluid shooting out near violently with each thrust and absolutely coating Magnus's only mildly flared spike. The loss of friction makes the larger mech forcibly strangle a whine from escaping. His spike throbs, flare thickening when it bounces up to hit his stomach with a wet slap, this time of it's own accord.
When Rodimus lazily slides off Magnus finally turns to him for the first time in this whole encounter. He gives no warning, only yanks him closer and mounts.
There's a brief scrabble as Rodimus is shocked out of his post overload haze by his rear hooves almost giving out under the weight. "MagnuuuuAAAASSS???!!" His question is quickly cut off with a squeal when Magnus's drenched, half flared spike is shoved partially into him. It takes three whole powerful thrusts, and just as many loud cries, for them to be sheath to valve.
There's no pause, as Magnus immediately begins a brutal race to completion, fucking into Rodimus, huffing and growling like a wild animal. The smaller mech can only stand there and take it, crying out as his valve is obliterated.
Already so worked up from the earlier frothing, Magnus's spike only takes seconds to fully flare and his overload to start. He continues to buck through it, gritting his teeth as he cries out himself.
Rodimus sobs as he's filled, the shear feeling of fullness sending him over the edge into a violent valve overload himself.
