Disclaimer: I don't own any characters; they belong to their respective owners.
Note: All characters are at least 18 years old.
It was late when Robin slunk back into Titans Tower after a full day of fighting crime. Keeping to the shadows, so as not to disturb any of the other Titans, Robin tiptoed past their rooms to his own. His sharp hearing caught the rhythmic breathing of Raven and Starfire, and Cyborg's occasional snores. He paused outside Beast Boy's room, hearing nothing. Robin shook his head. The shape-shifting Titan was probably out stalking a cat. He crept on. Robin stopped at his door, listening one last time, then entered his room. It was plainly decorated and neat, but to Robin, his room was home. Robin threw himself onto the bed with a sigh, still dressed in his costume, and closed his eyes. He was glad to relax from a long shift.
Robin's breathing evened out as he relaxed. One by one, he stretched his muscles so that they wouldn't become stiff. Once done, Robin let out a small smile, realising that there was one muscle he hadn't yet exercised. His eyes still closed, Robin's hand crept down his body, before curling around his lengthening cock. The tightness of his costume around his cock made it strain even more to free itself. Robin let out a soft moan, and ran his hand up and down his cock.
There was a creak in the corridor outside. In a flash, Robin was up, and at the door. He quietly opened the door, and looked outside. It was deserted. Robin shut the door behind him, and locked it. Secure inside his sanctuary again, Robin stripped out of his costume. Once naked, Robin lay back on his bed.
Free of his constricting costume, Robin's cock pointed straight up, perpendicular to his body. Robin gripped it again, his two fists only making their way most of the way up his cock. Slowly, Robin moved his hands apart, then together again. His cock twitched, and bead of precum formed at the tip. Robin swiped it away with a finger. Then, he tentatively brought that finger to his mouth, and licked it clean.
Robin sat up again. He twisted to one side, then the other, stretching muscles that were used frequently when fighting crime. When he lay down again, Robin pointed his legs in the air, then pushed them down so that he was bent in two. He slid legs along his body, and lifted his ass into the air. Robin hooked his legs behind his head. Now, his cock wobbled mere inches from his face. Robin could see another droplet of precum form at the tip. His tongue snaked out, catching the drop before it fell. Robin contorted his body some more, pushing his cock against his lips. His mouth opened to let it in.
Ever since Robin was young, he had been flexible. Even now, living with four other young superheroes, Robin was by far the most flexible. Only Beast Boy could get into smaller spaces, and only by turning into a rodent or cockroach. When Robin had discovered his body was sensitive to his touch, his flexibility always allowing him to get a more intimate view is his private parts.
It was only in recent months, though, that Robin had even thought about sucking his own cock. He had one day walked into Beast Boy's room unannounced to find his computer running. Beast Boy was nowhere to be seen, though the window was open, so Robin had assumed that Beast Boy had had to leave. Curious, Robin had flicked through the tabs Beast Boy had left open in his browser, and had frozen in shock as a video silently expanded to full screen. A man was curled up onto himself, his own cock halfway in his mouth. Robin had stared at the screen in a mixture of fascination and horror. Then reality had hit him. Robin quickly exited the video, and slid out of the room. It was just in time. There was a clattering in Beast Boy's room, and soon, the green Titan had walked out. By that time, Robin had made sure he was walking nonchalantly in the other direction. As they had passed each other in the corridor, the two Titans had looked in each other's eyes. Robin had nearly blushed. He had rushed into his room, locked the door, and jerked off until he had cum.
Over the next few months, Robin had gathered the courage to try sucking his own clock. It felt so good, that Robin now generally used that way to get off. He had quickly learnt that his flexibility meant that he could get much more if his cock into his mouth than the man in the video — his whole cock, down to the root, in fact.
Now, Robin used the skill he had learnt. Patiently, he thrust his hips forward, and his cock vanished into his mouth. Soon, his lips were pressed against the hair that grew at the base of his cock. Robin grimaced around his mouthful. He needed to shave again; he hated finding hairs in his teeth hours later. Slowly, Robin pulled his cock back until only the head was inside his mouth, then thrust in again, quicker this time. With every motion, Robin moved faster, thrusting his cock inside deeper each time. After careful research and experimentation, he had learned how to avoid choking himself, and now he could take his whole cock without even spluttering. Robin was proud of that, though he couldn't admit his to anyone else.
Finally, Robin pulled his cock out, and left only the head inside his mouth. As his tongue made intricate patterns on the sensitive head, Robin hands raced along his cock, jerking it so fast that his hands were a blur. When he came, at last, jet after jet of cum spurted into his mouth, and he swallowed it all.
Robin unfolded himself, and lay on the bed in a daze. As he drifted off to sleep, a pair of green eyes blinked at Robin from across the room.