I discovered this about 20 yrs ago from a chick giving me a blow job...i had never been able to orgasms from a bj and she had said she was a master and would make me squirt. At the time i didnt know what she meant by squirt lol
Anyways, she made me cum like mad and then she started teasing the glans lightly with her tongue and then i squirted. I was never able to self duplicate due to sensitivity after cumming, but few years later i was washing up in shower and noticed the same feeling when the water hit the frenulum area along with ventral side of glans and whammo...it happened!
Fast forward 20 yrs to jow and i can duplicate it pretty much every time...for me it has nothing to do with how full bladder is. It causes me some serious contractions and insane pleasure to where i can almost not stand. Sometime its dry contractions and sometimes i can hit ceiling of the shower. I dont know if its a special fluid or just piss, i really dont give a shit cause it feels so damned good.
I dont know how to instruct other on how to do, but i can share my observations over the years. It needs to be done within a few minutes of cumming or wont work, can be done soft or hard, doesnt matter for me atleast. Use very light pressure/friction, as for where, that depends on each person i would assume...but my two hot spots are the frenulum area and glans right at frenulum, along with the top side center of glans. I can do it by hand, but for me shower is easiest, and least messy place to do it lol. I recently got a nobra twincharger to masturbate and found out hard way to turn it off soon as a cum or else i squirt...i love it, but not a face full and all over couch lol
Hope this helps....
Btw...that video was funny at first, i swear she was laughing at the guy soon as she saw his tiny weewee