Only 1?
That would not do just to all the others I would love to see naked.
But from all the ones I would love to see naked, there is only a handfull I would actually like to play with.
And having seen my sister in law naked many times at the sauna, I can tell you it is fun comparing body shapes and size of siblings
... My BIL and I have had that pleasure many times ... and both sisters were quit amused and flattered one night when we compared out loud their breast size & shape (C vs DD), hairfashion down below (or lack off) and the shape of their pussy lips and ass.
So good luck to the ones who have SIL on their list.