Well, here is a basic tutorial on how to make the best of a small amount of space. I've seen a few threads on this, with people saying it is or isnt possible, but so far (to my knowledge) no one has done a writeup - here goes:
1 - First, you need a willing and able partner. Explain to her/him that there isn't much room, and the whole process will probably end within a half-hour or less as there isnt much space to maneuver.. cramping may occur. Also, this has only been tested on average adults.. I'm 5-4 and she's 5-6. So anyone significantly bigger, I can't guarantee it working out.
2 - Next, Location, Location, Location. Find a deserted street somewhere that isn't traveled often. Ex. A one-way street leading to an industrial location.. no one will be traveling it late at night so this becomes an ideal location. But in general, use your imagination and BE SAFE. Don't come back to me complaining that the cops busted up your fun.
3 - Next, park the car and properly secure it (Handbrake and leave in gear - just to be safe). Get out and switch seats. Slide passenger seat forward. Fully recline passenger seat until it reaches the aft-most stop. Then, slide seat back until it rests against the rear paneling. This will allow maximum space for movement.
4 - The Basics: I'm not gonna explain everything here. It simply isn't my job to give a birds and bees speech, rather simply to give suggestions on how to bang in the Z. That being said, regardless who owns the car, Guys have a seat in the passenger side, Ladies will have to go on top... sorry for all you doggy fans. I just dont see that as possible (maybe in the next how-to?) Its easy for the guys in this example, you can remove the clothes you need in the passenger seat. The lady will have to do that in the drivers seat. Or, if its desolate/warm enough, just have her get naked outside. If your not in such an enviroment, pants can be removed with care from inside the car.
CAUTION: There are many things that can be broken in the Z during maneuvering. Take care that while removing her pants that she does not knock into the rearview mirror, or put any weight on the shifter. Any force in the wrong direction could damage a synchro or gate.. and you dont need that kinda stress. Help her out by guiding her feet/legs while she is undressing and moving from the drivers seat to in front of the passenger seat.
Use the handbrake and gear lever to park, as without noticing at the end of the experience one of us had inadvertantly shifted into neutral. Not good on a hill. Handbrake to the rescue!
Use caution as to not let her lean on the Hazard Light switch. The last thing you want to do is call attention to the current situation and alert anyone within visual range that, "hey.. over here.. I'm hittin it in the Z.." The switch is placed in a retarded place, so mine went off like 2-3 times. A quick hand and reflex can keep this in check however.
Dont Forget: Use protection. I'm not responsible if you knock up your lady friend. So dont come back complaining if you forgot to wrap it before you attack it.
If anyone can add anything to improve this, feel free!