joli_toc_slide_out_box_top

Prerequisite: you must switch on the Top box option (under Slide-out TOC > Slide-out custom content boxes)

Add custom content at the top of the slide-out panel.

The container’s selector of the custom content is .wpj-jtoc--slide-out-custom-box-top

add_action( 'joli_toc_slide_out_box_top', function (){
    echo do_shortcode('[my-shortcode]);
});