Yes

As you stand in silence and shock you hear your sister say ‘John, is that you?’ you open the door slowly and you see her hiding herself with her pillow, you both go red as she says ‘how much of that did you see?’ in a quite tone. You mutter a quite ‘all of it’ and you both avoid eye contact ‘John i- idk what to say’ you jump in and say ‘look, Sarah how long have- have you had a erm- a penis?’ she covers her face with her pillow revealing her balls by accident and you can’t help but staring, she catches you looking and says ‘do you want to see it?’ and without you replying she removes her pillow to reveal her massive 12 inch dick standing proud at full mast