If this is something you'd truly like to work on, not out of a sense of guilt but because you would enjoy occasionally reciprocating, there are a wealth of resources out there for the enthusiastic amateur (you are far from the only would-be blow-jobber whose spirit is willing but gag reflex is weak). You have more options than "no blow jobs, ever" and "regular whole-hog sessions to completion that result in vomiting."
Mallory OrtbergIf someone you know is diagnosed with cancer, give them a call or send them a letter to tell them how sorry you are and to let them know how much you care.
Mallory OrtbergThere are few things more disconcerting than realizing the first date you thought went so well was in fact a dud.
Mallory Ortberg