can we have more of alpha dave being drugged, roofied, or encouraged (or forced? 👉👈) to drink more by dirk...need that man wobbly and disoriented
Unfortunately I do not have many ideas on it in my head right now.
I do think that Dirk would do so much research on what he should give a!Dave and how much of it. I think generally his dedication to making the drugging "safe" would border on neurotic. It's everything from side effect management to proper dosing to cycling drugs and dosages used in order to prevent (or at least minimize) addiction (since "safely" drugging a!Dave doesn't work if a!Dave gets the bright idea to take those substances on his own in places where Dirk can't control how much he gets.).
As always with Dirk in my mind, I think his default drug to use on someone would be ketamine. It's safe enough that it's used as an anesthetic in hospitals, it causes less respiratory depression than other anesthetics, it lowers heart rate less than other anesthetics. Dirk is not one to shy away from needles; he would just be very careful about using an alcohol swab and a sterile needle on a!Dave. If Dirk gets the dose perfect, a!Dave won't even remember what Dirk did to him while he was loopy. If Dirk overshoots it by a little, a!Dave will be distressed by the resultant symptoms, but it won't be life threatening. If Dirk undershoots it by a little, a!Dave will still be loopy and easy to push into what Dirk needs, but he might remember what happened the next day. Either way, the dosage is fairly forgiving, since the lethal dose is significantly higher than the low end of an unsafe dose (by a whole 5.5 times. Wow.). However, he would know that ketamine (and honestly most drugs) would be a serious risk if a!Dave had already been drinking.
I don't think that Dirk would be willing to drug a!Dave on top of things that a!Dave is taking voluntarily in general? Dirk is a little control freak and if he doesn't know the exact amount of any substance in a!Dave's body at a point in time, he'd rather wait until a!Dave is sober so that he has a fresh slate to work with, one where all of his calculations will be accurate and any drug interactions will be carefully orchestrated by Dirk himself.
This also doesn't apply to ketamine because there isn't such a thing for it (Dirk would just have to sit and wait it out and try to comfort a!Dave if he started getting paranoid and delirious and agitated), but I think he would keep antagonists on hand for anything he gives a!Dave in case Dirk accidentally causes an overdose. For example, if he gives a!Dave a traditional roofie with rohypnol (or any other benzodiazepine), he'd make sure he gets his hands on some flumazenil, just in case a!Dave's breath slows down enough to scare Dirk. He'd keep naloxone on hand if he ever used an opioid on a!Dave for the exact same reason. Because he cares <3. The rape is also because he cares.