How to slightly alter _layout for one specific page? I have a _layout which includes a contact button:
{% include '_contact-button' %}

This creates a small contact button in the bottom right of every page that when clicked expands into a contact form. I would like this to be on every page of the site except the Contact page as it has it's own contact form. Is there a way in the contact template to not include _contact-button while still using _layout? Something like {% dontInclude '_contact-button' %}?
Try putting it inside of a simple block as the default value...

{% block contactButton %}
    {% include '_contact-button' %}
{% endblock %}


Then on your one-off page, override that block with emptiness...

{% block contactButton '' %}


Untested, but that should do the trick!