And soon it is over

Jeanne:
Suddenly I push forward as my cock penetrates the crust of the planet
The unique sensation of that hot space on my cock as I start to thrust in and out
Every push destroys the continent as they generate extremely powerful earthquakes all around planet
Truly now the planet was shaking around it's axis as more and more the world ended by my thrusts
You could be hiding anywhere on the planet and you would still be feeling the tremors
I feel as soon I will approach my climax and cum
My cock only about 1% of the way down possible to the core

Circe:
The disruptions of your cock thrusting into the planet shift the tectonic plates around, and soon enough it's not just your actions causing the shaking- there's a huge realignment of plates going on that would cause the planet to tremble for days in your passing. The huge majority of shelters and bunkers are decimated by the destructive force, the only ones that remain are those with powerful shock absorbers stopping the shaking on every axis with a number of springs or a network of hydraulics. And even those are getting jostled. When you cum in the planet, there are yet more problems- the force of your sperm takes the path of least resistance, which, in this hyper-pressurized environment, is actually back up. Semen spurts all across the continent through cracks in the plating, leaving this whole half of the world with a variety of cumstains left on it

Jeanne:
My cum explodes from the underground as it exits almost like volcanos
Satisfied with my third orgasm I grow once again as my body reaches 500km of height
My cock 400km long as I feel more and more of the planet being moved apart
This was truly the last stretch as you start to see cracks appearing on the planet
There was no return now as I prepare for the next round
At this point there was no return chance
The cracking of the crust means the end as more and more i grow once again
1000km, 2000km, 3000km
My cock massive as it's size at 2600 km long penetrates the planet a forth of the way
Each thrust now deforming the planet

Circe:
You've made your way well and truly into the mantle of the Earth, and your cock is made delightfully toasty by molten magma, which moves aside obligingly at the thrusting of your incredible member. By now, your cock's sheer girth is causing it to impact many of the remaining shelters, with only a few that happen to be on the polar opposite sides of the earth to each other, perpendicular to the angle that you're thrusting at, surviving along with the last examples of this planet's life. But even there, their supports are crumbling, because the chain reactions are so massive that cracks are appearing far away from the point you're thrusting into

Jeanne:
My pleasure at the molten magma twists my face as I keep growing
My arms hugging the planet as I grow and grow
4000 KM,5000 KM 8000 10000KM
My arms are now holding the planet like a melon almost as my cock keeps thrusting in and out
"I think it will only sustain three more thrusts"
"Should be enough"
My voice booms around the planet in every place
First thrust my cock is already hitting the polar opposite side
My hands still holding together the planet
I pull and then...

Circe:
The planet is like a melting ice cream bar in your hands (except for the lovely warmth of the internal magma of course), in that by this point the only thing keeping it from falling apart completely is your hands keeping its basic shape together. Lava oozes out onto your fingertips, pleasantly warming them from the chill of space. Yet more shelters are exploded by the pressure of your fingertips, and now only 4 remain, in places where they're touched neither by your cock or your fingers. There aren't so much cracks now as there are soon-to-be-shards held scarcely together

Jeanne:
As my second thrust ends I start to prepare for my third and finishing thrust
My body grows one last time to 15000 KM as my cock finally goes through the other side of the planet
My almost planet sized balls unleashed as my cum comes out to the cosmos
My hands gripping the planet as even they can't hold it together now
My face in pure pleasure at the planet seizes to exist
Now just a asteroid field,filled with my cum

Circe:
It is the last testament to Circe's grand design that even this, this hedonistic act of mass genocide, does not wipe out the people in one final stroke. One last shelter is scattered into the asteroids, twisting through space, unremarkable among all the other debris. It's likely to hit a glob of cum or an asteroid in a few moments more, but for now all they can do is look up at your ecstatic face and still-pulsing cock with hatred and misery.

Jeanne:
Satisfied I come back to the household and meet Circe
"My dear head of research and development I have a gift to you"

Circe:
"Evening ma'am! To what do I owe the honor?" She asks, chipper as she has been since the reprograming

Jeanne:
"Well I think it might be useful to you to have a portal to that dimension you know?"
"Time dilation is still there so you could further any research you have by just sending a team of circes to spend 1000 years on it there you know?"

Circe:
"Oh well that does sound incredibly useful, yes! I'd massively appreciate it ma'am."

Jeanne:
"So I have opened a portal to it on your lab"
"It should be big enough for a bus to go through*

Circe:
"I'll be sure to make great use of it ma'am. How did your fun with the planet go, if I might ask?"

Jeanne:
"Amazing,really unique experience"
"To see them struggle and try to win as I proved again and again it was the end for them brought me enormous pleasure"

Circe:
"Great!" She says, cocking her head and smiling cutely