I wish I was smart enough to think of this question but it wasn’t me, someone was nice enough to send me the link to this Hashkafa.com thread about the topic. It is real enough, especially if you had just eaten something charif (halachic translation – onions transfer taste) and then kissed someone the taste may transfer, I sure as hell know garlic would transfer, but why would you kiss someone who had just eaten garlic?
They should have also asked if you could kiss someone who was fleishig if you had just eaten milchig?
The replies to the thread are pretty interesting actually…
“If one thing leads to another she will be soon enough.” (reference the innuendo of her getting meat)
“or he’s getting fish.” (oy such dirty people)
There are probably tons of halachic questions that could be asked on the topic. There could probably be a whole gemara. Like if he kissed her but there was no toungue, or maybe there was heavy petting or how long was it since the woman brushes her teeth? Lots of variations that I don’t want to get into.