It wasn't until I had tens of grams of ketamine and used most of it over the course of a summer in addition to DXM that I finally began experiencing the characteristic "hole" effects from dissociatives alone (radical proprioceptive distortions, strong visuals, sensations or visions of flight, etc.). At that time I had already been using dissociatives for years, including IM ketamine up to 250 mg (I weigh 175lbs) -- which just incapacitated me with quite a bit of motion-induced nausea. I think some people need to "learn" to get those effects for whatever reason, be it through a subconscious mechanism, physiological adaption, or otherwise. Of course I don't recommend increasing your use on the off chance that doing so might just happen to work for you. Doing so is far more likely to cause semi-permanent tolerance than anything else. I only mention it because that's what was correlated with the beginning of those effects in me. Prior to that I needed to use ketamine with a powerful tryptamine to get the "hole" effects (IM synthethic psilocin [7-14mg], synthetic DMT [50-70mg], or DPT [50mg]). Those combo experiences also almost definitely played a role in "learning" to "hole" with dissociatives on their own.