Twins

[If_Only_]

The Twins had been doing things siblings should not do for years. They are so in tune with each other that they can often communicate without words. Entire sentences can be exchanged by means of finger movements, eye blinks and maybe some barely audible verbal ticks. They can do it in ways no one else even notices, almost telepathically.

While out with another couple they would never suspect, they are presented with an offer for some evening fun. This other couple is very hesitant to even make the offer and have a fear of how they'll all react if it doesn't go well.

There is a moment of tension. The twins look at each other and converse in their own private way.

The other couple is confused, then relieved when the twins agree and accept.

Who is the other couple in your story version?

 

[dirk2024]

First....the twins. Are they identical boys/girls or are they fraternal boy and girl?

The other couple...since you're already working the taboo angle with the siblings...is to have it be their aunt and uncle. Kids enrolled in college in another city, where aunt and uncle live. They have a small house in their backyard and offer it to their neices/nephews/whatever. But there is a condition.

Aunt and uncle are nudists and there is a pool/hot tub in the back yard.