where Geek Sam and
>> Alternate Jack
>> get it on the past and real Sam and Jack feel it
>> simultaenously in
>> the future?


This? Was actually the plot of an old skool Fantasy Island. Ventriloquist (female) brought her (also female) dummy to life...and felt everything the dummy did. Dummy was no dummy and went after the guy the girl was sekritly!pining for and sexed him.

...no, I swear to God, I am not making this up.