Disclaimer: I own nothing!
This may be a two-shot...depends on what people think of it...
Make Me Bleed
Deidara bit down on his lip hard and tightly shut his eyes, praying that his Danna would not notice the effect his ministrations had on him. He was not ashamed of his tendencies, but could not bear to see his Danna look at him with disgust. He opened his right eye slightly to gaze down at Sasori roughly but diligently working.
Sasori threaded a fresh needle and began to work on sewing the deeper lacerations covering Deidara's body. He gave the task his full attention as he pushed the needle hard through his partner's flesh, glancing up to see Deidara with his eyes shut and an expression of pure ecstasy on his face. Sasori was taken by surprise at Deidara's reaction, the sight was the most erotic he had ever seen and if he could he would have preserved it forever as the ultimate art. Never taking his eyes off Deidara's face, Sasori tightened his grip painfully around the blonds' upper arm and dug the needle down much further and harder into the flesh. Deidara bit through his lower lip at the unexpected sensation and looked directly at his partner, lust evident in his visible eye.
Sasori took this as his cue and forced his fingertips into one of the other wounds, forcing the flesh to tear further. His young partner threw his head back as he gasped in pain and pleasure. The puppet-master felt for the first time in his life desire as he watched Deidara. He pushed the blond forcefully down onto his bed and straddled his waist, taking a kunai from his holster. He used the razor sharp blade to cut further into Deidara's flesh as the blond alternated between moaning in ecstasy and gasping in pain.
If it weren't for the pain Deidara would have believed he was dreaming. He had fantasised over the thought of this exquisite torture countless times, willing his Danna to cut him and hurt him after every fight, to tend his battle wounds while creating new ones. He looked straight at his Danna as he took the kunai Sasori was using to his lips, running his tongue along the blood-covered blade, cutting it, creating more of that delicious red liquid all the while never breaking the eye contact with his Danna.
Watching the blood run freely from Deidara's lips as the blond laughed in pleasure, Sasori would have admitted then and there that art was transient in its nature. Sasori had long thought himself incapable of human feelings and had believed that he would never experience desire, lust, or love as payment for his immortality. But seeing Deidara writhing beneath him slick with sweat and blood he knew that he had always been capable of those emotions.
"Danna…hurt me, torture me, make me bleed, please," Deidara whispered.