The concept of "hot" and "cold" slots refers to machines that seem to pay out frequently or not at all

https://www.slideserve.com/morvinqugc/top-10-tips-for-enjoying-your-time-at-the-gambling-establishment-s-ports

The principle of "hot" and "chilly" slots refers to machines that appear to pay out ordinarilly or by no means, despite the fact those traits are lastly random.