Step-Sister's Freaky Friday

You and your StepSister are playing a video game and she beats you again! You snatch the handset off her, maybe a little bit too hard as you accidentally electrocute both of you in the process! You open your eyes and you feel... different. WTF why are you looking at yourself lying on the sofa!? Feeling your body it has lumps in places that weren't lumpy before... are they TITS!? This has got to be a dream!! You try and wake your StepSis but it's no use. Emergency services thinks this is some sort of prank. Great, your life is ruined trapped inside of your stupid StepSister's body!
Or maybe it's not so bad after all... you cop a feel of her tits and wow you never knew she was such a hotty. It would be awkward if she seen what you was doing right now but fuck it, you may never get this chance again. You slide your hand into her panties and your pussy is wet already, OMG this feels incredible. You finally make yourself cum, finding yourself becoming addicted to "strumming one out". Maybe this is a blessing in disguise! The only thing that could make this thing a whole lot more exciting is if you had a cock in there...
You immediately call your Mate to come over, at first he thinks it's a prank but when you show him your tits he realises it's you, your boring StepSister would never do that! You know he's always wanted to fuck your StepSis so why not make the most of this unique opportunity. Yeah it might be a bit weird, but it's just two mates having a laugh. Doesn't have to mean anything, and technically it's not two blokes having sex when you have a vagina.
But what you didn't realise is that you would swap back to your original body when you get impregnated... leaving your poor StepSister mind blown as to what has just happened!