Gaining

Tease back.

You shouldn't tell her to try it you should ask her to try it.

And yes, I think you should ask her to try it.

My advice is looking better now, isn't it? If you'd kept it at a teasing level it would allow you to explore the subject without it getting confrontational, as it apparently did!

Please answer the question! Thanks.

^^^
THIS.

If she's not interested in it, it's not going to matter what approach you take.

And if she's so frequently breaking up with you over silly stuff as you've said, then find someone else.

And I really just want to say how incredibly arrogant you are here. You give two words of advice and then demand to know whether or not it worked and brag about how things would be so much better if only he'd listened to you better.

Your relationship advice given in this thread is ignorant at best and disregards pretty much everything aside from that she may have been teasing the guy about it (though he wasn't even sure of that).

Given the other advice in this thread, odds are he'll benefit far more from the flat-out discussion of it rather than your vague suggestion to "tease back". And he'll certainly benefit more from a relationship where arguments are not ended with emotional blackmail.