You laugh merrily. "A man? Oh Tanith! Denial will not help you now!" Lazily you begin to walk towards the gender-confused half-fox. "But I can."
A few feet away Todd continues to wrestle with his manhood, trying to coax it to remain. But he feels like he is losing. His lust is building -- but it isn't lust as he has known it. As your scent begins to seep through his forming muzzle into his subconscious, his desire builds -- not to empty his balls, but to be filled from yours. Even with his eyes closed, the vision of your maleness is burned into his sight, and your triumphant scream mixed with Astrid's submissive pleasure still rings in his ears.
"Ohhhhh Goooood..." He clutches harder at his maleness, feeling it shrink from his fingers at your approach. He hardly remembers why he's struggling, as each huff of laboured breath draws your scent in deeper, cementing you in his mind as the dominant male.
"Oh Tanith." You step across him, your paws to either side of his thighs -- which spread a bit more, instinctively giving you access. You shake your head down at him, pity mixing with the flames of your desire. "Open your eyes, Tanith."
With a whimper she complies. She. Tanith whines as she realises she answered to the feminine name suggested by Astrid. But the thought quickly fades to the background as her eyes again fix on your vulpine maleness, the scent not only of your cum but of Astrid's vixen juices drifting down to her sensitive nose.
"I'm scared," she whispers. "I never thought..."
"Shhhh." You kneel down, over her legs. "Let go of your human thoughts. You will be so much happier as a vixen. Let me show you."
Firm but gentle you take her hands -- still mostly human, save for the coating of fur -- in yours, and lift them away from a cock barely as long now, erect, as it was flaccid. You move them to her first pair of breasts and guide them over the growing swell. Then you release them, to tease at her nipples with your thumbs.
"Therrre," you purr. "There is nothing to fear. This is you. Your flesh. Your beauty. Your pleasure..."
"Ohhh..." Tanith's eyes close again as she tentatively massages her new mammary tissue. "M-maybe..." This isn't... so bad...
Feeling her start to relax, you grin in satisfaction, your cock growing to full hardness once again; and you slide yourself forward until the long, thick phallus is resting atop her small one. Growling possessively as your balls settle heavily upon her own shrunken orbs. You feel her tense a bit at the intimate touch, but she relaxes again as you continue to talk reassuringly.
"This is nature's course... as you said..." You begin to hump, frotting against her, chest rumbling as your feel her maleness surrender and recede, dwindling with each pass of your own mighty cock. "Your nature... always... to be a vixen..."
"Oh -- Tanith -- yes," huffs Astrid. Sparing her a glance, you confirm that she's begun fingering herself to the sight of you dominating her hapless boyfriend. "Give in to him! -- it feels so -- wonderful -- to be filled -- by a fox!"
"Aaaa-Astriiid..." Tanith groans, shudders, feeling the last bit of resistance fade. Filled... by a fox... Filled... by a fox... Filled... by... a...
"Foooooox...!"
Her balls tighten as your knot passes over them, and then as your length slides down, you feel them vanish. Your growl of victory mingles with Tanith's moan of final submission; and as your cock slides back up, her empty sac smooths and parts into dark lips kissing your member in adoration. And then --
For once your own sound of triumph is drowned by Tanith's shriek of surprised pleasure as your grind your knot on what remains of her cock -- a super sensitive nub poking out of its clitoral hood. Her hands clamp down, squeezing her breast tissue, involuntarily sending another wave of intense pleasure crashing through the first.
"Foo-ooox..." she pleads. You lean down, nuzzling and licking at her snout. Fully formed now, tipped by large, triangular ears bent back in submissive. The hands that mash her breasts are claw-tipped and padded; the brush that wags through the leaves between her legs is a yard long and bushy with rust-red fur and white tip.
"Vixen," you reply, half-teasing, half-encouraging. "Feel it. Embrace it."
Tanith's eyes flutter back open, glistening now with need, and she stares full into your mysterious golden orbs, molten with power and confidence. She finds no words, and you lick her dark brown nose.
Then you pull away, and began to slide up her body, your phallus plowing through the fur on her taut stomach. To either side, her breasts expand in greeting, rising up in glorious roundness to cushion your maleness as it passes between them. She tilts her muzzle down to watch, awestruck and still a little unsure, a long moan rising from it -- broken by gasps as your muscled rear slides over her stiff nipples.
Larger and larger you watch them grow as you begin to titfuck her in earnest. From a lagging B her main pair grows to E as you saw between them. Tanith gives in fully to her body and begins to knead them against, encasing your girth in her satin-furred flesh, her eyes feasting on the shining head as emerges from the tunnel she has created for it.
"Yesss, vixen," you croon. "See it, smell it... taste it, if you wish..." And at your words, her long vulpine tongue slips from her muzzle, licking off a bead of pre-cum, tasting the remnants of the union between you and Astrid.
You feel her body jerk.
"Oh, fox, I can't --! Can't resist you any longer!" She looks up, eye bright, hardly ale to speak through her panting whimpers. "Please --! T-take me! Make me -- fill me like Astrid! Like a fox!"
"Gladly, my vixen." Deftly you slide back down, trim muscular chest coming to rest firmly atop her octet of boobs. You push your arms beneath her, hugging her to you, savouring the squish of the female assets against your chest. Tanith moans, returning the embrace, desperate now to confirm her status as submissive vixen, to know the joy of having a strong, loving todd hold her and protect her.
You wriggle your hips a little as she squirms under you, lining up your sexes, then you push in. It takes Tanith a minute to warm up to the new sensations, but she is eager, so eager, and the Moon guides her instincts. Soon your tempo is increasing, and Tanith is begging for your knot.
Astrid too pants, her tempo rising in time to yours. She can't believe it. She never dreamed that when she came out her with Todd for a romp it would turn into this. A vixen! So wild, so free, so powerful. So full of warm seed, and hungry for more! Her fingers slide in and out of her snatch like lighting, her other hand mercilessly tweaking the new nipples you gifted her with.
"O-oh fox!" cries Tanith. "I can feel it! I -- vixen -- want -- need --"
"Shhhh." You lock your muzzle around hers in a deep kiss, tongue probing and caressing the inside of her long, narrow mouth. Then you release her to whisper, "Here --
It --
Comes."
Your whisper turns into another triumphant scream as for the second night that night your cocks swells in token that you have successfully turned a human into a submissive mate. And Tanith's vulpine ring tightens in answer, confirming -- along with her voice -- that this is what she was meant to be. And Astrid, hearing her boyfriend finally commit to being your vixen, chimes in with her own yowling climax.