Someone (usually but not always a woman) needs something from someone else (usually but not always a man). So Alice lays on the liplock, and when Bob recovers from post-kiss bliss, he finds out that his wallet, or key, or secret plans, or map, or weapon, has been stolen. Or his enemies have all escaped, or sneaked into the castle, or he's been chained to his chair. Of course in all this kissing, the kisser usually gets more than she (or he) is bargaining for and gets a little carried away her/himself. Examples: