My cock twitches and strains desperately against the familiar metal of the small chastity cage locked tightly around it, as the plug in my ass lightly vibrates, my frustrated mind immediately distracted by it, along with the taste of my master's cum from his recent blowjob, driving me insane with need. 

I let out a quiet whimpering moan and move my hips slightly as I feel the familiar discomfort. I only have three weeks left before unlock, my cage only locked on for a month at a time. Although if I want to I can beg my master to fuck me, to bring me some relief, to make me cum in my cage, but it comes at a price, an extra week in my cage. No, I've done that so many times, I've been locked in this cage for over a year now, my one month release always just a month away, I need to be strong if I ever want to be released and have an erection ever again, to be able to get hard without the crushing discomfort, to be able to touch my cock, to feel a warm hand touch it rather than the cold hard unyielding metal that grips it now, to be able to bring myself to orgasm and control my own pleasure, to relieve my swollen aching balls, to decide when I get pleasure and when I don't, which would probably be every day. 

I try to focus on my work, every now and then having to stop for a moment as the plug moving inside me gently teases and torments me, my hand subconsciously reaching down to rub the metal covering my denied cock, wishing that I could gain relief. I try to remain strong, just a few weeks, that's not long, I can make it, I just need some self control. 

I freeze as master steps from his bathroom into the bedroom as I put his clean clothes neatly away, his naked and wet body on full display, his large cock in full view, immediately sending my mind crazy with desire lust and need, drowning out any other thoughts, consuming me, my cock straining harder than it has all day. I can't help myself, I can't resist any longer, I need relief, I need it now, I can't wait three weeks. I struggle to focus as I walk towards him, my eyes staring hungrily at his cock. I drop to my knees and look him pleadingly in the eyes. 

"Please sir, please fuck me in return for another week in chastity?" He smiles down at me, as I willingly keep myself locked away and denied, reduced to begging for chastity, something I'd said I'd never do when first locked up for a month over a year ago.

"I feel generous today slave, I'll accept your offer and give you another week in chastity if that's what you want." 

"Thankyou sir." I quickly get off of my knees and climb onto the bed, remaining on all fours and raising my ass into the air, inviting him to use me, to enter me, to my me his bitch. I moan slightly as my plug is pulled out, my stretched and ready ass twitching with need, impatiently waiting to be filled. I feel the bed shift as he climbs on behind me, please fuck me master, I need your cock inside me. I gasp in pleasure as his cock thrusts into my ass, my hips moving back and forth in time with him, making him reach deep into me, silently moaning as he fucks me, my hands gripping the sheets as waves of pleasure flow over me, my cock straining painfully as it swings uselessly beneath me, my heavy, full, aching balls dangling and swaying, as his balls slap against my cheeks. I cry out in joy, my body shaking as I build towards the edge, holding it as it builds, riding the wave to its peak, before cumming hard in my cage as his warm cum fills me. My body collapsing onto the bed, my mind lost in bliss, my body twitching from the pleasure, as his cock slides out of my well used as, my buttplug put back in place, sealing in his cum inside, keeping me ready for use when I inevitably beg to be fucked again. 

As his cock pushes against my lips I open my mouth and begin to suck and lick him clean, enjoying the taste, my cock twitching in response. 

I watch as my master leaves, my mind clearing from the blissful orgasm, thw ever constant need growing once again, realising what I just did, the week of denial undone, trapped in my cage for 4 weeks again, never moving forwards, always with a month left in my cage. Next time, I'll definitely be stronger next time, I won't beg for more time, I won't beg for his cock, I won't beg to be fucked. I feel my cock strain in it prison as I think about him fucking me again, desires already taking over, deep down knowing the truth, knowing that I'll always choose chastity, that my frustration is a choice that I willingly choose every week, that my eternal chastity and denial is decided by me and me alone, my master giving me exactly what I want and ask for.