I've had apartment neighbours fucking plenty of times, but one time the girl went totally out of control screaming at the top of her voice, and got mad that we complained...it was funny, because then she wrote us a note asking us if we 'could agree on a schedule'. We said 'no, dear, you may please keep it down, as we have informed the landlord' (who thought it was hilarious, by the way.) When it's been more discreet, it's been a bit exciting to hear it. I used to hear my Lesbian neighbour upstairs sucking pussy, and didn't need to jack off to that. Mostly with roommates, it's me making the squeaking from jacking-off noise.