I have noticed that when I vape DMT, I can hear liquid moving around in my internals. I'm guessing that there is an initial relaxation mechanism that allows things to move around you a little more freely and I'm guessing the bladder is no exception.
I've got into the habit of getting into a near state of urinal meditation while sat on the toilet before I administer my dose. Even the slightest hint that I may have to urinate would make me feel uneasy when entering hyperspace.
So sparing no graphic details, here's what to do if you suspect urination may shortly follow but isn't urgent, but you want to speed things up a little. Unfortunatley I can't say this will work for the female of the species for obvious reasons
1. I find it's best to do this sitting, as you can be more overly relaxed.
2. Retract foreskin in a way that makes your penis point sort of downwards into the bowl. This will open up the urethra and ease the overall pressure needed to eject. Sometimes when I get up to urinate in the middle of the night I'll go for round two before leaving the bathroom using this particular technique to get rid of the shy wee's
3. Gently and slowly tickle the area around the small of your back and your kidneys. I'm not sure of the science involved, but ever since I was a child it causes an almost tickle-like ich sensation which will cause me to urinate.
4. Closing the eyes and breathing slowly also helps.
Now with good practice and fine tuning, this method should be able to deport even the most anxious of wee's!