You smiled a little trying to contain your laughter as you decided to keep quiet. It would be a dirty joke but still funny to hear her reactions.
"Nick?" she asked a little louder.

One second of silent. Two seconds. Three Seconds...
"Nick!? This isn't funny! Please...please answer me..."
You continued to stay silent and then you felt an earthquake again as your sister began shaking her large breasts vigorously. She was panicking a lot now. Her heartbeats were more than enough to say that.
You were unbelievably dizzy and a little cold from the shake. You were going to have to speak out really soon.
You finally heard your sister crying. "Nick...no...no...I killed him. I...I can't believe I agreed to take him in...I'm...I'm so stupid!!"

"Sis! It's alright! I'm alright! You can stop crying now...uh...that shake woke me up," you excused though you knew that you were just trying to pull a joke on her which wasn't funny anymore.

"Nick...Nick! You're okay! I thought I lost you for a minute! Don't...don't ever do that. Please give me an answer...I...I love far you too much to lose you like that..."
You hesitated a little. "I love you too..." It felt odd since you couldn't say it as if she was your lover. She was your sister for god's sake!

"Oh thank god...it seems that you're evenly distributed between my breasts..." she explained. You were a little confused as to how that was possible. You moved around a little to try to understand better and you found yourself in a cradle like position. Your body was also curved since it felt like your lower back was attached deeper than the actual breast. That worried you a little.

"So uh...what now?" you asked feeling a little satisfied now.
"Anything you'd like my love..." she whispered which seemed to travel deeper than her normal talking. It sent chills to your spine and erected your dick. You remembered that you could say anything and it would be done in a snap with Rose...it didn't matter whether or not it was possible! You knew you'd have to say the right words though.