Tickle Abuse
How about, a couple goes away on vacation and stays at an uncle/friend's house while there away. The aunt/uncle/step mom/colleague have bondage equipment and makes tickling videos - like a Tommy at Tickle Abuse. The couple finds the equipment in a room that's off limits of course. They see something with a url or maybe written on the stocks and look it up. They see what the equipment is used for and decided to try it out.
One of them gets locked in and the other person can't figure out how to unlock them. Embarrassed they have to call the aunt/step mom/colleague whoever to confess what they did. The home owners then call a friend/model who goes over to help but only does after both members are tickled as punishment (per the homeowners request). Maybe the homeowners have to come back because they have the keys and tickle them for ruining a weekend away.
I'm a big fan of self bondage, for example after he/she finds the equipment they strap themselves in and realize they cant get out because they dropped the key or something. Then they are later found by the homeowner or a house keeper or something.
Usually more of a f/m fan, dont usually think of many */fm scenarios.