Huge fast breathing worked for me yesterday!
I've been in a cycle of attacks for 12 days, taking Verapamil, and asked to get prescription of O2 but doctor said they don't prescribe that. (Going to see neurologist today to see if they do.) I started getting a daytime attack yesterday morning, and started "hyperventilating" if that's the right word - taking huge deep breaths, sucking air in and pushing it out rapidly, to try to mimic what I've seen people post about using O2 for attacks. Attack aborted in about 5-10 minutes. Started coming back half hour later, so I did the breathing again, and aborted in 10-15 minutes and no extreme pain.
Thanks for sharing about the Wim Hof technique - seems similar to what I did, I want to look into that... I know I have a problem with shallow breathing when I'm stressed or when I'm too much in my mind - not sure how that is related to CH or the regular headaches I get when not in a cycle, but definitely seems like oxygen and breathing is a factor.