What Causes My Head Rush?

Head rushes appear to be triggered by a variety of factors, like experiencing a drop in blood pressure from standing up, hyperventilating, sucking down mass O2 from a mask and other, less legal factors.

What I’m wondering in light of my google-fu failure is which if any of these types of things cause my head rushes (along with squiggly sperm-like wiggles appearing in my peripheral vision momentarily, as well as a “high-head” spinal tingling buzzing feeling) when I hack my brains out in a coughing fit (because I am an ashamed smoker)?

I suspect massive oxygen intake from sucking breaths between coughs during a brief fit, much like a hyperventilation buzz, but I am not sure. I know full well I need to drop the coffin nails sooner or later. I generally get these in the hot shower in the morning when the steam loosens everything up and I go on a coughing jag and uh, expectorate brown lung oysters (which thankfully slither down the drain with nary a touch of encouragement from my big toe).