Is this a bus you want to be on? Is it taking you somewhere you would like to go? The final destination may be somewhere very unpleasant and difficult to get back from.If the thought is unhealthy, make the decision to get off the bus. When I do this I visualise pressing the button, hearing the buzzer it triggers and feeling the bus slow to a halt. I step off the bus and into the warmth of the sun.
It helps to have a place to go immediately; I like to think of three things that I’m grateful for (new things each time) so that my brain does not default back to the unhelpful thought. If gratitude practice doesn’t appeal to you, choose something that you like to think about. A healthy problem for the brain to work on is an ideal distraction – what your next art piece will be, what to have for dinner, what to do on the weekend etc – anything that can engage the brain long enough to change course.
It takes quite a lot of practice but can be powerful – especially when adapted to suit yourself. Allow yourself to be curious because some thoughts need to be investigated or explored (and some very important thoughts make us uncomfortable), but become an expert at recognising when it is a good time to get off the bus. With time, just pressing the buzzer may be enough to switch the thought off.
This tool can be a good one to teach kids too. I hope that is helpful. Good luck!