My girlfriend is interested in my vaping and likes trying my flavors, but anytime she puffs and gets vapor she starts coughing. she can smoke just about any cigarette/cigar just fine. ive tried having her vape my juices as 100% pg, 50/50 pg/vg, and a few drops of only vg to see if it was only pg that was causing it. she fills her mouth with vapor then when she starts to inhale she just starts coughing. any tips for her to try to not cough? she can blow it out her nose sometimes without coughing...