Accidentally dropped the cone piece (or 'bowl', depending on where you grew up) down the high school boys' toilet after having a sneaky toke halfway through a class.
My friend was pissed off that I'd managed to clumsily lose the most vital part of our "school" smoking apparatus (a small black bong that's resided in one of our lockers) - especially as i had go elected to go 'first' in our risky - but apparently very I important, at the time - hijinks.
But when I suggested he reach into the s-bend to retrieve it, he suggested I fuck off.
I didnt
flush it - not my style at all

Regardless - this was a totally unintentional "flush".
This was many years ago, but happily I graduated with sufficient grades to get me into the university/course i wanted, where I continued to smoke weed - only in much, much more pleasant settings than a cubicle of a high school shithouse.
I've never lacked...er, I mean
had the restraint that would have me flushing anything psychoactive, or otherwise drug related...I have always been more inclined to use 'other' (highly efficient) drug disposal techniques.
Logic never really caught up with my inner fiend - except in hindsight, when there was none more to be taken but supply - in such cases - was never sufficient enough in quantity to fall into the "
regrets buying" category.
"
Regrets taking" - sure. But never resolved it with a flush.
"What goes around comes around" is not - unless i've been grossly misinformed - a reference to the passage of drugs into the sewers, via the toilet bowl....
Nor has the opportunity for any last minute 'evidence disposal via WC' been possible; or necessary - as it turns out; when a some of the bright young lads from my local constabulary were kind enough to pay a 'friendly visit' - they were not able to distinguish the "drugs" from all the other crazy shit in my apartment. Which saved them a lot of hassle, really - as I'm a peaceful, law abiding citizen. That's not drugs, occifer - it's ..uh, an art piece. Strange, now that you mention it - yes sir. Art
is pretty weird today - I agree with you there
...And that? Yeah - that's...for....my art.
Fortunately their bewildered reaction when confronted with a living museum of such unusual artefacts, books, musical instruments and various weird "works in progress" (artistic or otherwise) as my residence was at the time - meant no further explanation was requested, or offered. Less awkward for all concerned!
So my..."art pieces" in-the-making were able to continue without disturbance. Or meeting a watery undignified end with a hasty flush.
"Waste not, want not" as my 94 year old Grandmother would say. Right on, Gran