You hunt for some relief

You just can't face getting into a hot tub, as horny as this, with not only your own naked body, which seems desperate to fuck you, but also your own ex-girlfriend, and your former best mate who stole her off you. It is just too demeaning - especially given what you can sense about how this body feels about both your body and Mark...

You have to find a way to relieve this tension.

Having removed the vibrator, you experience two new sensations.

The gentle buzz that Jo, in your old body, no doubt thinks is tickling your pussy, is now tickling your fingers. It feels kind of nice, or fun...

...but what feels less nice and less fun is the sense of emptiness you feel in your temporary pussy. You realise that ever since you swapped you have had something in there pleasuring you.

You drop your fingers to your pussy and gentle stroke the lips. You shiver and groan as you make contact. They are so sensitive - and touching them sends such a thrill throughout your groin, and radiating across your whole body, particularly centring on your now rock-hard nipples and your throbbing clit.

Within a moment of exploration, your fingers are drenched. You are so horny. That libido pill is working havoc on you.

You splay your fingers, separating the folds of skin that form the hood of your clitoris with two fingers, then press your palm into Jo's - your - sex, grinding it gently as you slip your thumb into her - your - pussy.

This was exactly how you tried to finger her, as a man, and you'd thought it drove her crazy. Now you knew exactly how it did.

The sensation of grinding on your own clitoris, while you penetrated yourself and thumbed your own G-spot, was unlike anything you'd ever experienced. You were in ecstasy.

As you ground away, rolling your hips against your palm and your thumb, you used the vibrator to tickle your rock hard nipples. That sent further shockwaves across your body.

You were putty in your own hands.

As you drove away at yourself, your mind again wondered back to that memory of you - no, Jo's body - with Mark. That leather collar encasing your throat, just tight enough so you could feel it, always, but not too tight so that you couldn't breathe. Your complete vulnerability to Mark - and anything he might have done to you.

The tension, and expectation, as he teased you, kept you waiting... and then the sense of completeness, of perverse safety and security, of absolute surrender as his cock energetically thrust into you unexpectedly. How it felt to be pulled back by the hair onto his rock hard erection.

As you thought about it, you rocked harder, and began to emit a low moan... It was almost as though your thumb, although far too small, resembled Mark's cock deep in you, and your palm his slapping balls. You imagined it was actually Mark pistoning into you.

Again he was fucking you like you’re his toy. Deep, relentless, possessive strokes that made your whole body rock forward.

As you get more and more aroused, you begin to visualise Mark in your head. How he now towers over you. How his broad chest could envelope you. The square cut of his jaw. His strong shoulders.

Although the idea is weird, you feel yourself getting even wetter as you think of him, and odd, comforting waves wash over your whole body.

You find yourself whispering his name, "Mark".

The taboo of whispering your old friend's name as you fucked yourself with your own fingers in your own new cunt turns you on even more.

As you feel yourself ascending a hill towards the release of climax, you begin to pant, "Mark... Mark... Mark..." in time with the rhythm of your grinding hips.

As you get closer, and closer, you find yourself moaning, the vulnerability of the sounds turning you on even more... "Oh, Mark, yes, fuck me, fuck me, fuck me... make me yours. Mark... Mark... Mark..." Your pussy almost clenches as you think of your friend - with the dick you've seen countless time before in changing rooms - pounding it in real life.

The joyful but deranging frustration of trying to hang onto your orgasm until he permitted it...

"Oh Mark... oh Mark..." you pant louder.

You're close... you're so close... in your mind you just need his permission, just as he would be about to explode into you, inseminating you....

"Please, Mark..."

Just then the door slams open.