Something between #include and #extend with sass - include

Question

Is it possible to include a css rule in sass without duplicate the code?
With extend we are extending the code, but i dont want that eiter. I want include it, without duplicating code.
For example
SCSS:
.heading {
font-size: 16px;
font-family: my-cool-font;
}
.box {
background: red;
h1 {
#extend .heading;
color: white;
}
}
.my-other-box {
.heading {
color: black;
}
}
HTML
<div class="box">
<h1>My heading</h1>
</div>
<div class="my-other-box">
<h1 class="heading">My heading</h1>
</div>
CSS
.heading, .box h1 {
font-size: 16px;
font-family: my-cool-font;
}
.box {
background: red;
}
.box h1 {
color: white;
}
.my-other-box .heading,
.my-other-box .box h1,
.box .my-other-box h1 {
color: black;
}
So the two last rules there are because its extending (I understand the benifits of it).
But if i want to both use classes, and extends i dont want it to extend, just include it. But i dont want it to duplicate the code.
I want:
CSS
.heading, .box h1 {
font-size: 16px;
font-family: my-cool-font;
}
.box {
background: red;
}
.box h1 {
color: white;
}
.my-other-box .heading {
color: black;
}

Answer 1

If you use an extend class (or use a class name that differs from one you're repeating elsewhere), you can get the output you're looking for:
%heading, .heading {
font-size: 16px;
font-family: my-cool-font;
}
.box {
background: red;
h1 {
#extend %heading;
color: white;
}
}
.my-other-box {
.heading {
color: black;
}
}
Output:
.box h1, .heading {
font-size: 16px;
font-family: my-cool-font;
}
.box {
background: red;
}
.box h1 {
color: white;
}
.my-other-box .heading {
color: black;
}