It *is* hot. Sadly, the only thing I've seen like this are kind of "DIY" projects that get pretty intense with soldering and whatnot.

And of course there is the DreamLover2000 - if that is still in business. Their website is still up.

http://www.dreamloverlabs.com/dl2000.php

After searching, I found this:

https://fancysteel.com/collections/advanced/products/advanced-chastity-trainer

Which can also be worked into a collar.

https://fancysteel.com/collections/advanced/