Leo Valdez sauntered into Dr Mason's office without Betty introducing him. The doctor knew Leo quite well. After Leo had technically died during the Blood of Olympus quest, and had been subsequently returned to life using the Physician's Cure, his girlfriend Calypso had insisted that he went to Dr Mason for regular checkups. Dr Mason didn't doubt the efficacy of the Physician's Cure – he never doubted his father's own work – but he was still happy to see Leo a few times a year. Leo had, in fact, been Dr Mason's first experiment, and, Dr Mason always thought, also one of his greatest successes.

Leo sat himself down on the chair, and smiled up at Dr Mason.

"What's up for today, doc?" he asked cheekily.

"Regular check up", Dr Mason replied. "Unless you have anything interesting to add."

"Same old, same old", Leo replied. "The Physician's Cure hasn't failed yet." He looked down at himself. "At least, I don't think it has."

As quickly as only a demigod with ADHD can, Leo jumped up, and leapt onto the bed. Dr Mason stood, and slowly followed him, his asklepian in his hand. Leo's feet tapped impatiently on the side of the bed as the doctor approached.

"Come on!" he said, his hands fiddling with a few wires he had pulled from his pocket. "I've got some projects to finish."

Dr Mason tapped Leo lightly on the head with his asklepian. The wires fell from Leo's hands as they dropped into his lap. Looking into face, Dr Mason could see that it was blank and emotionless, a far cry from the fiery demigod the he had just been.

"Leo?" Dr Mason asked. "Are you with me?"

"Yes", Leo replied.

His voice had also changed. Before, it had been expressive and passionate, filled with nuances that came from speaking two languages from birth. Now, Leo's voice was hollow and flat.

"Tell me about yourself", Dr Mason ordered.

"I am the Legendary Electronic Object 2000, a prototype anthropomorphic robot", Leo said in a monotone. "My purpose is to serve my master in whatever way I can."

"And who is your master?" Dr Mason asked.

"You", was the curt reply.

"Good", Dr Mason said, sitting in the chair that Leo had vacated. "Now, please show me the exercise I set you at our last session."

Quickly, Leo stripped out of his clothes, his limbs moving carefully, as they were actually made from metal, and powered by electricity. Then he lay back on the bed, and pushed his legs behind his head. Dr Mason smiled. It had takes months to get Leo flexible enough to do that. Of course, Leo had never suspected the reason he was suddenly interested in exercising was a suggestion from the doctor; instead, he thought it was to look better in Calypso's eyes. Now, though, the exercise paid off, giving Dr Mason great views of Leo's body.

Leo slid a hand down one of his legs, and pressed a finger at his asshole. His entrance opened up easily, due to the regular exercises Dr Mason had set for him. Leo plunged his finger deep inside him, then added a second, and a third finger. Slowly, he withdrew them, then pressed his fingers in again. With deliberate actions, Leo fucked himself with his fingers.

"Very good", Dr Mason said after a while, when he saw that Leo's cock was hard and leaking precum.

Immediately, Leo withdrew his fingers, disentangled himself from his contortionist position, and stood to attention in front of the doctor. His cock also stood to attention, pointing directly at Dr Mason. Leo stood still, barely moving, as the doctor's eyes raked over his body. Even when Dr Mason stepped forwards to run his hand down Leo's chest, and to grip his cock, the demigod didn't move a muscle. Finally, Dr Mason stepped back.

"On your knees!" he ordered.

Leo dropped to his knees, his hands hanging limply at his sides, and his mouth open. Dr Mason unzipped his pants, and took out his own cock, which was achingly hard. He wiped it across Leo's face, leaving a trail of his precum behind, then pushed his cock into Leo's mouth. The instant Dr Mason's cock touched his lips, Leo's mouth closed around it, and he began to suck. Dr Mason pushed his cock up to its root, then pulled out again. In previous sessions, he had taught Leo not to choke on his cock, as robots didn't have a gag reflex, and it had worked wonders. When Dr Mason's cock was all inside Leo's mouth, the doctor could see a bulge beginning to form in his throat, and unless he held it there for too long, Leo wouldn't choke.

After fifteen minutes, Dr Mason thrust deep once more, and came. Leo's throat contracted around his cock as he tried desperately to swallow the doctor's seed. Dr Mason pulled his cock out, glistening with Leo's saliva, and glanced down at the son of Hephaestus. At the same time as Dr Mason had cum, Leo had also orgasmed, as instructed. Quickly and efficiently, Dr Mason cleaned up the Latino demigod, and dressed him. Then he tapped Leo with his asklepian again. Leo blinked a few times, then wiped his mouth, and if getting rid of a lingering taste.

"Are we done?" he asked. "I've got to get back to my experiments."