Certainly! Take the painkiller

You happily drink the glass of water considering how awfully thirsty you were, and swallow the pill without objection - probably an aspirin? Whatever it was, it doesn't matter since you will be a guy again in a few hours from now. "Tell you what, let me get one more thing so you won't have to bother with a shower until tomorrow morning." He turned around and walked off before you had a chance to ask what he meant, but considering he was going to come back, you were in no rush to chase after him.

The minutes somehow feel like hours, though... you were getting pretty damn tired, pretty damn quickly. After such an eventful day however, it was to be expected. Stifling a yawn, you eventually see your dad returning with something in hand. When he opens his palm, you see him holding a... string-less tampon? "It's a little trick my wife uses pretty frequently after we did it bareback. She doesn't want to leave the bed and go all the way to the bathroom just to squeeze the cum out of her pussy. Using this trick lets you go right to sleep, and in the morning you can use the toilet and pull the tampon out to give the cum a chance to leak out of ya. That's what the sleeping pill was for, too. You deserve some rest after taking two loads like a champ."

Huh...? It was a sleeping pill? Wait what did he mean with cum inside the pussy, wasn't he wearing a condom with you the whole time? Awfully tired as you are, you reach down to pull the blanket off your crotch. Your eyes widen in shock! Not only was your labia swollen to twice its normal size and blood-red, but blotches of cloudy, white sperm were smeared across your pussy lips! Your gaping womanhood was so loaded to the brim with milky semen that you could see it pooling right up to the entrance into your body!

You begin to realize that you had been completely wrong about two things. For one, the pill obviously wasn't a painkiller, it was a sleeping pill. Secondly and most importantly, that empty condom wrapper you found earlier, was really just a random, forgotten item. Not only did you seduce your dad into fucking you bareback, but you also milked multiple batches of cum directly into your painfully receptive pussy! Even if there's only a few hours left on the spell, this was terrible!

"Here," he offered with a generous tone as he bent down and wriggled half of the tampon into your aching cum-slot, coaxing a gasp out of you. The half that was inside you began to swell rapidly. "If we do it like this, it will first soak up all the useless juices that belong to you instead of any sperm." When the first half of the tampon finished expanding, he pushed the second half inwards and you watched the tampon disappearing into your body. "There. All safe and packed away." He leaned forward to give you a soft kiss on the forehead, while you felt... a need to panic, but the sleeping pill was in full effect by now. You felt... sedated and sleepy.

"N-nuh..." was all you could whisper, barely even audible at this point. As your father stood back up, you were face to face with his flaccid penis and the purple cockhead attached to it. It was much smaller and less frightening now in its current state. It knew that it had fulfilled it's natural purpose - by pumping multiple thick loads of your father's sperm into your completely unprotected vag.

With what little strength you have left, you try to get up... but it's no use. You drop right back down into the pillow. Your thoughts are all about the way your father's lil' swimmers will have plenty of time to get very deep inside you...

Your petite hands reach down, you desperately need to remove the tampon...

"No, Sara... just leave it inside until tomorrow morning." He slaps your hands away, and for good measure, places his fingertip against the bottom end of the tampon and gives it a good push, squishing his semen into the far back of your naked vag.

With no energy left, your vision goes black and you fall asleep...