It's become a must have for both of us. The frequency of her doing it is determined by her, but it's turned out to be everytime, "I gotta have your cock in my mouth." It turns her on tremendously knowing that she can do it and how it feels to me when it disappears. And the feel of her lips on my base, mmmmmm. An advanced version is to insert all the way in (with her looking up at you with her baby blues ) then feel her stick out her tongue and lick your balls. And now that her gag reflex has gotten even less, she also likes me to sometimes hold her head while I thrust all the way in and out.

It is definitely a learned skill. Similar to learning to put contacts in your eyes without blinking. It takes awhile to become proficient, but the rewards are plentiful for both. My awesome girl learned on me, as well as my previous girl. My size is on the upper end of average, and they are on the petite side, but overcame any perceived notions on whether they could do it or not. I'm sure it didn't hurt being horny all the time and high on the kink scale.

Very happy and lucky guy,
Scott