Since he first learned to make a fist, Trunks had been getting the shit kicked out of him by his dad. It appeared to Trunks that since he had been affirmed to be male, his destiny was to be his father's punching bag. He was told it was to toughen him up, to teach him that his enemies wouldn't go easy on him, to fight without restraint. Never had he doubted the actual reason. Everything, always, had been about Vegeta's pride. He survived to attain pride for his fallen race. The man martyred himself before noon each day, had died multiple deaths for imaginary brownie points from his dead dad. Somehow, he found pride even in winning a fight with an eight-year-old. Whether it was to repent for reproducing with a human woman, or just the thrill of watching something, anything, writhe on the ground, he continually forced his son into training session that inevitabley ended with blood and laughter.
As he grew older, stronger, and angrier, the battles became longer. For every punch he got in, his father retaliated with ten more, but the satisfaction of seeing that embarassed, surprised, and somewhat hurt expression replace that smirk always numbed the pain and kept him going. And as they became more and more evenly matched, Vegeta's winning taunts grew to be more aggressive. It was not uncommon for Vegeta to sit on his son, call him names, or spit in his face, always to be punctuated with a remark about some fight wherein Vegeta had succeeded, but Trunks would have failed.
Trunks was fifteen, boyish in the face but showing manliness in his silouhette. In his work-out pants, he showed the growing breadth of his shoulders, the size of his hands and feet belying the fact that he would soon surpass his father in all physical dimensions. His father, imperceptibly slower today than yesterday, and slower still tomorrow, was currently assailing him with blows, most of which Trunks managed to deflect without too heavy of an effort. The occassional successful blow was, unbeknowst to Trunks, weaker than he ones he had recieved at age fourteen, which were weaker than those at age thirteen. What Trunks was unaware of, Vegeta hadn't ceased thinking of since he was told he had a son—Trunks was getting stronger as he aged, and Vegeta was getting weaker. It had taken fifteen years, but today, Trunks passed him.
Without thinking too deeply, Trunks blocked with one arm and threw a punch with the other. To his mild surprise, it collided with the side of his father's cheek. In the fraction of a second it took to pull his arm back, he noticed something—rather than lifting his own arms to block, or throw a punch, or anything, his father's posture slagged, distracted by the pain in his teeth. Trunks threw another hit unconciously, hitting his dad square in the nose, inciting a blast of blood. Still, his father curled ever so slightly in on himself rather than properly defending. After a third blow across the teeth, Trunks' mind went blank with confusion and mild satisfaction as he assaulted his father down to the ground with a torrent of punches.
It took a full minute for Trunks to recognize the blood coming from his own torn knuckles, and appreciate what he had done. His father was lying on his back, his chest jerking roughly with the strain of breathing. His face was a bloody pulp, covered in purple bruises splitting as they swelled. Several teeth were missing, and a fluid contrived of blood and saliva rushed from the corner of his mouth at an alarming rate. Trunks stared, trying to overcome his emotions, trying to work up the strength to walk away, to maybe get help, anything. He failed.
A stream of nervous laughter streamed out of Trunks' mouth. Quickly, it evolved into hysterical chuckles, doubling him at the waist. Between gasps of euphoria, he managed to stammer, "I...can't...believe...you...you..." He swallowed, attempting to calm himself. "You...dad, you lost! I beat you! I beat you like a little bitch! Look at you! I destroyed you, you...! You...you picked this fight! You challenged me! And I...I beat you! Dad, I'm still a kid, and I..." he erupted into more senseless laughter, over a decade of tension running out of his body through his rapidly babbling mouth. Cheerfully, he brought a wad of snot down from his sinuses and planted it confidently on his father's face. Vegeta gurgled as his son's mucus slid down the split bridge of his nose, mixing with the blood.
"How's that feel, you old bitch?" Trunks laughed, wiggling his hips as if trying to subdue a happy dance. "How's that, you old, stubby little inch-dick bitch? Holy shit, this feels amazing. Ha! Look at you!" He grabbed a fistful of his father's hair, dragging his upper body a few feet off of the ground. He shook him roughly, relishing the sight of his father gagging on blood. "Fifteen! Fifteen years, you've been torturing me, kicking the crap out of me just to feel like a big guy. But you're not a big guy, you're just a sniveling little bitch that got his ass kicked by his teenage son! Fuck! This is amazing! Dad! I'm gonna fuck you like the little bitch you are!"
Vegeta's eyes flashed with awareness, and he weakly lifted his arm in protest. With a jerk of his wrist, Trunks smashed his father's skull to the hard ground. Without skipping a beat, he brought his dad's ass up, ripping his pants along the seam. With vigor he removed himself from his pants, tucking his growing erection over the elastic. His father whimpered for mercy, and the sound only incited Trunks to grin wider as he spread his dad's ass and plunged inside, unlubed.
The sobering sensation brought Vegeta back to full consciousness. He screamed in agony as the dry flesh of the inside of his ass tore, his son's thick cock ripping its way in and out. Trunks laughed, spanking his dad arythmically, leaving pink handprints on his hip. Gradually, the blood began lubing his way. The feeling of hot wetness and the sound of his father's screams brought him to the edge, and he slowed down to prolong the endeavor.
"Dad! Hey, Dad! Say, 'I'm a slutty little bitch who loves getting fucked by my son.' Say it. 'I'm a slutty little bitch who loves getting fucked by my son'." Trunks looked anticipatorily at the back of his dad's head. After a few seconds with only the slap of his balls against his dad's taint and panicked whimpers, he gave his dad a sloppy punch in the ear. Trunks felt his dad's ass tighten with the pain and shock. His tongue began to loll out as he gave his dad a few encouraging slaps on the rear.
"I'm...a...a slutty little bitch..." Vegeta sobbed in humiliated anguish.
"Who...loves getting fucked by my son..."
Trunks squeezed his dad's ass in both hands as he began to come, pounding with angry, bloody thrusts into his father, spilling semen both inside of his ass and on his back, along with the back of his hair. Vegeta's body went rigid at the feel of the hot liquid gushing into his body, the pained shivers only extending Trunks' orgasms.
When he finally finished, he pulled out, tucking his bloodied cock back into his pants. For a moment, as he observed the sight of his dad, beaten to a hideous, malformed shape, weeping, and covered in semen, he felt a twang of guilt. However, it passed rather quickly. He padded out of his room in his bare feet, tossing back the comment, "I won't tell anyone if you won't, old bitch."