Jack Hunter, 19 year old student

You wake up groggy and confused. You can't quite remember yesterday's night, and given the dream you just woke up from, you must have been drinking. Still in a sleepy haze, you put on autopilot and start your morning routine: you put on boxers, shorts and a shirt, and start shambling towards the toilet to take your morning piss.

Still, it would be silly, would it not? "Peeing on women's clothes". So many things wrong with that. It'd be so unpractical for society as a whole: women clothing would have to be made extra absorbant as to not dirty the surroundings - or worse, said surroundings would be absolutely covered in piss stains, and... yuck. You shudder at the thought. Plus, what about toilet paper? It'd probably be a non-issue for women since they'd be wetting themselves anyway, but you, for one, don't want to dirty your underwear with the few last drops.

As you start getting more in touch with your surroundings, you realize a few things.
First, your sister is wearing pink, cotton pajamas, which is highly unusual for her; she always was more of a tomboy-ish type when it came to clothing.
Second, since you can see her laying asleep on her bed, you must be in Lucy's bedroom.
And third, judging by the sounds, sights, and the fact that you're holding up her blanket with one hand and aiming your cock at her with the other, you must be pissing on your sister.

...

Holy shit you're pissing on your sister!

You physically freeze and mentally panic as you piece together what you just did: you mechanically got out of your room, went to her bedroom, snuck in, and as if out of habit, deliberately lowered your pants and lifted up her blanket to use her as an urinal. Out of habit?! You're pretty sure that in all the 19 years you've known her, you never grew such a habit!

And then it hits you. The dream. The presence. All this talk about peeing on women's clothing. It sounded insane, illogical, a non-sequitur the likes of which you only get in dreams... And yet you acted on it as if it were perfectly normal. And now your sister is bound to wake up and find you absolutely soaking her pajamas with your piss - gosh, since when did you take such long morning piss ?!

You finally unfreeze as your stream begins to dwindle. You move your gaze to your sister's face, shaking in fear...