Creating a donate button but for a 3rd party

I just created a free website that provides a fun service for anyone who wants to use it. One thing that I would like to do is add a donate button, but the donations isn't to me. When user clicks the button it would redirect them to a third-party website's fundraising page.

How can I cleanly and unambiguously demonstrate that the donate button is not for donations to my website? I think people will be more likely to donate if the donation is for some good reasons rather than directly to the website. So far I have tried a button with the text Donate (to a good cause) I've also thought about changing the text to Donate to X Charity

However, if I use that then the users are going to wonder what X charity has to do with the website at all. Ultimately, I want to tell the user "if you like this website, please consider donating to my favorite charity".

My website's header with the donate button: