I have a sister, super nice and super beautiful. Every time we go to a nightclub, we sleep together. I really want to fuck her.

Since she doesn't mind sleeping with you (you didn't make it clear, I temporarily understood that you slept in the same bed, but you didn't have sex), isn't her meaning obvious?

Let me tell you a joke:

"A woman and a man sleep in a bed at night. This is the first time that two people have slept in the same bed.

So the woman said to the man, if you sleep in bed at night and sleep on my side, you are an animal!

So this man did nothing all night.

The next day, the woman was speechless and said to the man, you are worse than an animal! "

This is just a joke, there is no other meaning.

The meaning of this joke should be obvious. You go to nightclubs every day to prove that you are not stupid.

My suggestion is:

You, a godsister, are willing to sleep next to you, which means that anything can happen to you anytime, anywhere. If you do, she won't refuse, and it will happen naturally.

You can do it. After sleeping with her, you can call her sister. The relationship remains the same. You can hug her when you're done. Ask her:

"Later I also call you sister, ok? I am younger than you. Although my place is very big! If you want to be my girlfriend, I will be very willing. If you don't want others to know about it, I won't affect your social life. I will respect your wishes and I want to hear your opinion. "