(You're Ranma's sister who is also cursed. When dumped in cold water you turn into a man. Both yours/Ranma's father and the father of the Tendo's are out on a few days vacation to catch up with each other leaving you 5 alone for a while / The door is open, and you see Ranma greeting you in)

"Hey sis!" He leaps onto you hugging tightly with stupid grin on his face

"Uhmm... Ranma.. Thats a.." Nabiki trails off looking you up and down before smirking "A very attractive man!..."

"I must agree... Thats a man Ranma..." Kasumi speaks up also confused

"Wait... Don't tell me!" Akane rushes off returning with a tea kettle of hot water, opening the top and throwing hot water on you, making you revert to your original female form

Everyone's jaws drop. For the sole exception of Ranma of course { Like that Gojo Satorou reference I dropped at the end there? ;) }