Edward grasped the Colonel's jacket and buried the lower half of his face in it to muffle himself as he let out a low moan; his toes curled, his legs clenched around Mustang's sides. He felt so full there, and he panted for breath as soon as he could trust himself to be silent.
He could feel Mustang's lips on his neck at the Colonel smiled slightly, and fingers tightened on Edward's neck and hip, his back pressed against the couch's armrest. He shifted, taking his time, letting Edward adjust and letting himself get comfortable, before he kissed Edward's neck and started to move his hips back, and then up into him again, agonizingly slow.
Edward stifled another moan by biting the material of Roy's jacket, one gloved hand going up to tangle in the Colonel's short hair as he wrapped his other hand around Mustang's back; he panted against his neck and gasped, "Faster, you rat bastard, not like this," and shoved his hips down on Mustang's erection.
The Colonel's laugh might have been relieved or wanting or even mocking; it was hard to tell. But he obeyed, stabbing up into Edward with a sharp jerk, faster, and harder, a soft moan escaping his own lips as his rough gloves slid down over Ed's spine. The hand at his hips glided around the dip of his thighs to touch his groin, brushing his erection and drawing a strangled gasp out of Edward, before grasping him more firmly, stroking him, the sandpaper quality so unique and different that Edward was left breathless, arching into the touch.
Mustang's erection struck something inside him then, and Edward saw stars, his whole body seizing, and he heard himself demanding, "Again, ah, again—!" in a strangled voice as he clutched himself tighter to the Colonel, his mouth and teeth against the Colonel's neck as he breathed harshly there, his hand grasping Mustang's hair, refusing to let the Colonel lift his head from Ed's shoulder.
Mustang's hips pressed up against Ed over and over as they met somewhere between themselves with each thrust. Edward was shaking, and he sensed the precipice nearing, coming closer now with every sweep of the Colonel's hand over his erection and every drive upwards of his hips. He squeezed his eyes shut and turned his head into the collar of Mustang's shirt and enjoyed the pleasure of teeth gently biting his neck, of rough material skirting his shoulders, of fingers squeezing his length, until again, that place inside him was brushed up against. It propelled him over the edge, skyward and beyond, as he bit the Colonel's clothed shoulder and groaned, muffled, arching his back, eyes wide and unseeing as he climaxed hard, every muscle stiffened.
He felt it when the Colonel shoved up into him again as deep as Edward's body would allow, felt it when Mustang grunted against his neck and stiffened as well and heat blossomed deep inside him. And then they were sagging against each other, Edward's fingers still tangled in Mustang's hair, Mustang leaning over Edward and resting his weight against him, warm and wet.
"... someday," Edward said, "I am going to borrow your gloves, and see what you think of them."
Mustang smiled against his neck. "Mm. I'd like that, Fullmetal."