J.S.
I've had this. I was told by my ENT that it's the sinuses draining what's probably an infection. It could be pollen, it could be mold... we think it's mold because it's happened to me year round. I would be drying my hair upside down or reaching for something on the ground and feel a pop up there and when I stood up there would be this... this... FLOOD of flourescent yellow pouring out for a minute and if I blew my nose it would fill tissue upon tissue. Near the end, it sort of looks like a gel. I always feel much better once it's emptied out.