We've done loads of what we call fantasies, (like LittleMissCali all restrained by the imperative of safe sex) but places can also be the fantasy rather than the sex act.
For instance, we'd love to have sex in one of those old fashioned railway carriages, the ones with the individual compartments which hold say 8 people. It would either be a FMF or MFM scenario, time limited to the longest time between the stations on that line. If a MFM, just us three people in the compartment, it would be Shel just lifting her skirt, knickers off, get shagged by me, I come up her and the other guy (we know him) then gets sloppy seconds with him in a condom, finishing just as the train comes into the station. Cocks back in pants, Shel pulls her skirt down just as someone enters the compartment. Then notices the knickers lying on the floor......oops.
Anyone got a private railway ? You can watch.