Luckily, my room might as well be an apartment. Two louvered french-type doors open into a wooden L shaped privacy screen which leads into my main room... which then connects to my own hallway with a closet to the left, and a bathroom straight ahead (with shower, etc). I've done it everywhere from the toilet (with all seats down, me sitting down and sitting on my lap facing me... to my bed, which vibrates and goes up and down (double-size hopsital bed...)
I've also rented numerous hotel rooms for when we're feeling more frisky than privacy would otherwise allow at the house; in the back of a car, which as someone else said isn't really that comfortable; in a friends apartment; at her house... Use your imagination! If this is your first time sleeping with the girl I don't recommend you saying "Hey, let's try it on that playground's merry-go-round...", you might be better off spending 40-50 bucks on a decent hotel room, after a good night out and a few drinks in you both to loosen ya up... good luck.