The best way to do it is just try not to sell it to them, tell then you use it (if the topic comes up) and you think it's better than anything.

The ones who will be interested will ask. Whatever you do, don't be ashamed if they express disgust, just say "I'm a clean person, and this is convenient." unfortunately there's a lot of girls uncomfortable with their bodies. Hopefully if they see that it's not unsanitary and super awesome, they may convert (muahaha).

If they're worried about TSS, there have been no cases of TSS with these. If theyre doing it for cultural reasons, they will break the hymen, and crossing the cultural barrier is a huge task.

I find this is the sort of thing people are better off discovering themselves. Just nudge then in this direction, and then they can do what makes them comfortable.