Is there a trick to Divination Distillate?

I'm trying to figure out how to be able to rely on being able to trigger the flask effect for more than a few microseconds, and I just cannot get it done. Are there particular builds which are able to incorporate it easily into a flow?

It's a Health + Mana flask.

So like any other Health + Mana flask, it deactivates once it runs out of stuff to recover.

Ergo, make a build that is constantly hurt/out of mana.

For example, I recall someone using Soul Taker in combination with Fevered Mind jewels to keep their mana bottomed out to keep mana flasks up (It was for Soulthirst + a 14s base duration mana flask rather than DD but the theory is the same)

But yeah, easiest way would be some sort of Soul Taker/Kingmaker build with horrible mana sustain to keep the flask active.

Not sure if it's possible to actually sustain a damaged health state or otherwise balance mana expenditure to being equal to that of the restoration of the flask.

You can use a Sapping life flask to remove mana and guarantee uptime. If you're an Eldritch Battery build you can keep your mana regeneration at very low levels to ensure that a single use of the sapping flask will get you decent duration, also without disrupting your skill use. This will require you to have some of your mana unreserved though. Another option is to be a low mana cost build to begin with (like, a golem or RF totem build that barely casts anything that costs a lot of mana), or you can prevent mana costs in other ways while keeping your mana usage high (Vaal Clarity, Soul Taker etc.).

i used to use it on my summoner back in the days. i would just hold down my curse button and my mana would deplete faster than it could regenerate even with the flask.

you can also use doedre's exixir