You ask: How to stop thinking? I say: Just watch, be alert.
And drop this idea of stopping, otherwise it will stop the natural transformation of the mind. Drop this idea of stopping!
Who are you to stop? At the most, enjoy.

And nothing is wrong - even if immoral thoughts, so-called immoral thoughts, pass through your mind, let them pass; nothing is wrong.
You remain detached. No harm is being done. It is just fiction; you are seeing an inner movie. Allow it its own way and it will lead you, by and by, to the state of no-mind.

Watching ultimately culminates in no-mind.

No-mind is not against mind: no-mind is beyond mind.
No-mind does not come by killing and destroying the mind: no-mind comes when you have understood the mind so totally that thinking is no longer needed -- your understanding has replaced it.