Bro! Ixney on the OpsecretTey! haha You may as well ask for the location of the Ark of the Covenant. This is everybody's Holy Grail quest once they get knee deep into DIY. As such, this could be the greatest thread of all time. I have the exact same experience, and little clues have been dropped in many other threads.
Surely it's different for different types/profiles of recipes, but I agree there's something similar in many (good) commercial juices that just adds a certain "body" ...maybe better expressed as something not PG/VG related and nor really tied to flavoring themselves. So think flavors that add mouthfeel and little flavor ..like coconut at low % and White Chocolate (TPA).
I try and capture these type of secret sauce ingredients when casually mentioned on the Forum, and that would include saline and vodka. @AaronR I don't think it's a cream but has that same kind of thickness.. great post!
@Ghettotrout pass me some of that popcorn, Imma sit back and watch the show