This one is really simple, yet works wonders.
I've only tried this while chatting, texting or talking on the phone with the target.
What I do is raising buying temperature as lot as I can, so she feels momentarily safe. And if I don't know her that well (or simply haven't kino'd her much in real life), I throw in conspiracies so our rapport get lot more of a "you and me" feeling.
Then I simply write/tell her something along the lines:
"Haha you know, the next time we meet I WILL kiss you"
The trick is to time this WHILE her buying temperature remains high. Obviously I change the line a bit depending on the situation, and it's even better to have a date set (so she can't back out).
Another key factor is my confidence. I'm not asking for her opinion, I'm stating that I've made up my mind and that I'm 100% gonna kiss her. But I still remain playful, as if it's not a big deal.
If done right, she will in "worst case" laugh along and freak out a bit, but she WON'T SAY NO (I actually haven't failed this routine once, so I have no idea what to do if it does hahaha).
Then next time you meet her, you can kiss her whenever the time seems right.
Happy kissing folks~
PS: If you're absolutely sure a kiss is too far away in the escalation, you can foreshadow a light kiss on the lips instead. But I'm not sure what english word to use instead of kiss (I mainly game in Swedish).