Make him your sex .

You pant and then pound your soft, fat chest with your fist. It makes meaty, wet plaps with each impact. "You were always such an asshole to me just because you were bigger and older! But nah, now I get to be the bigger man here! I get to be in charge!" Then you simply bend over, and your one-ton belly pins your brother to the floor, covering most of his body too. He helplessly squirms and thrashes against it, gasping for air, but is completely helpless.

"You know, big brother," you say with a chuckle at the irony, "this body seems a bit difficult to use. I don't know how I can jerk off again, what with my cock buried an entire foot inside my fatpad. I'll need help. and you look like a good candidate. Come on, what do you say?" Your brother pauses, and his face turns red, and it's not from oxygen deprivation.

"I-I..."

"If you do a good job, well, you know I have some power now. I could maybe give you back some weight."

Your brother moans a bit at the idea. "Yes, please, I'll do whatever you want, just make me big again!"

You smile and stand back up straight. Your brother scurries back from under your belly, but doesn't move any further. His skinny cock is standing at full mast. You can still taste the powder on your tongue, so you say, "I wish my brother was my bitch, willing to satisfy my every sexual urge. I wish he'd know I own him, and that he'd never wear clothes again unless I order him to. I wish to be able to add mass to people and grow them according to my desires, so I can reward him for good behavior."

Your brother is about to protest when he suddenly stumbles backwards. A black collar materializes around his neck, clearly displaying that he belongs to you. His eyes go glossy, adopting a thousand yard stare as his brain rewires to fit your wants. He then drops to his knees, cock at full attention, and gazes up at you longingly. You chuckle and waddle back to bed. When you sit down on it, it immediately shatters and your ass hits the floor without any resistance. Your body wobbles like a jelly for a few seconds from the impact, but you're not even hurt, even though you know you can't stand back up on your own.

"Come here, slut," you say, beckoning. Your brother scrambles towards you, happy and eager. You point to your huge swollen fatpad. It's so large that the skin that would normally be your scrotum is just a small, wrinkly, hairy patch partway inside the pit with your cock. "Go in there and suck me off until I climax. You're not allowed to come up for air until I do. I want you to drink every last drop."

"Y-yes sir," He says, before prostrating himself and putting his head into the cavernous pit with a wet plop. You can suddenly feel his tongue licking the tip of your dick before it's enveloped by his mouth. He starts sucking on it and a shiver runs up your spine. You start massaging your nipples and you try to hump into him, but hundreds of pounds of flab stop that movement. He realizes what you're trying to do, however, and starts bobbing his head up and down your tiny nub dick. You start breathing heavily, you feel the pressure build, and then you finally cum.

Your brother milks every last drop out of your dick, just as you ordered him to, and it was a bigger load than you had ever made before. He pulls his head out from your fatpad and gasps for air, patting his stomach. "You could've filled a cup with that," he groans.

"What a good boy," you say, and then you wave your hand. As you had hoped, his frame starts to fill out a bit, but not with fat, but pure muscle. He looks disappointed.

"What about my belly?"

"Hey, I said I'd make you bigger. And I need to get back up on my feet, and I don't need a useless fatass right now. So pick me up."

Your brother obeys, of course, squatting down and pushing against your sweaty flab rolls on your back, slowly making his way down to your ass and lifting it up off the ground. Finally, you're back on your feet, leaning against the wall. You grunt and pant, before telling him "good job," and waving your hand. With a gurgle, his stomach swells outwards, burying any trace of a six-pack. His fat belly is nothing to brag about, and it barely hangs over his waist, but at the sight and feeling of having some softness back, your brother immediately grabs his dick.

"Don't," you command. His hands instantly fly off and he holds them behind his back. "You exist now for MY pleasure. You are not permitted to masturbate. You can only cum when I tell you to. Be thankful I gave you some fat at all. In the future I may give you more."

He nods and steps away. His cock throbs, but he doesn't touch it. By the way he's squirming, you know he wants to jerk off, but you figure a few weeks of edging is just what he needs after how he's treated you your whole life.