Finn has a huge thing for Poe acting like a sadistic, pervy military commander, yelling at him and humiliating him during sex. It's not because he was abused during Stormtrooper training--that was strict, but carefully monitored for signs of abuse. It's just that part of him misses being told exactly what to do and showing off his skills, and it's way more fun when it leads to sex.
Finn/Poe, military kink