Yes

"Of fuck ok!" You take off your clothes, until you stand there in your boxers.

"What makes you think you can stay like this? Off with it!" she says.

You are pretty hard by now, so you don't feel good about doing this, but what else could you do now. Just leave won't make it better?

You take a deep breath and pull down your boxers, your hard-on springing up!

Your sister's jaw drops. "Oh my gosh, you little bastard. You got hard."

"How on earth is that my fault? I don't control that"

"Oh I will teach you some control," she says and stands up. "Give me yours clothes."

You reluctantly hand over all your stuff.

"Now..."