Originally posted by Godsize
Yeah...
1: Place hand on girl's head.
2: Push down forcefully.
Haha, yeah, that is probably the best way, although girls generally don't like it when you try to lead their mouth up and down your cock.
I guess you could have her practice on a banana or something (or your cock for that matter). I think a lot of it has to do with how deep the girl's mouth is, which is for the most part, in proportion to her body size. Regardless, I'm sure over time the gag relex can be overcome, as she will just learn to ignore the reflex.
I don't really have any useful advice, other than talking to the girl and seeing her thoughts on the matter. Although, obviously the topic could come off fairly awkward.
I don't really care about a girl being able to deep throat, as it seems that most girls I have been with have had another problem. I can sum this problem up in five letters...T-E-E-T-H. I swear, the last girl I was with nearly drew blood from me. But that is another issue entirely.
Good luck on your mission.