Mononoke, Medicine Seller/otherself, fangs
(Note: just in case context is needed, this is connected to this fic, which is basically my personal fanon of MS sealing his other self by screwing him.) ---
Sometimes, it is like this: his other bound and growling, straining to break free.
He smiles, a baring of sharp, neat little teeth. "No..." he murmurs. "Your part is done here... for now."
Sometimes, his other comes to him willingly, remembering their purpose, their one desire. Sometimes, it is like this.
By the time he is guiding his other's cock inside him, sliding down onto it with a hissing breath, his other's fangs are sinking into his flesh; he jerks, grimacing as his skin tears, as his other laps at the blood that flows forth. To maintain balance (in retaliation, he admits to himself with a smirk,) he winds his hand in that silvery hair and yanks his other's head back, scrapes his own fangs down the long, brown line of his other's throat. The blood that trickles between his lips is incidental; the same blood runs through both of their veins.
His other gasps, jerking up with a strangled groan, thrusting deep inside. The resistance never lasts for very long.