They don't have a safe word
Hey, if you're kinky more power to you! It's 2017, if you're not sex positive, you're the outlier. But if your boyfriend or girlfriend takes it a little too far, it's time to establish a safe word. If they don't want a safe word, they're not someone you can really trust during BDSM or erotic asphyxiation. After all, they're sociopaths. So if they kill you (accidentally or intentionally, of course), they would probably be able to pass it off as an accidental death because they're notoriously conniving and can readily lie under oath.
And look, if they're really good in bed so you wanna keep them around for at least a little longer but don't want to risk being a victim of manslaughter, at the very least insist on having a safe word that doesn't rhyme with "harder," "faster," or "butthole." When they're slaying in the sack, make sure you don't actually get slain in the sack, ya know?
But if they're the Jan Levinson to your Michael Scott and pretend not to hear the safe word, video tape you during sex to analyze with their shrink later, and make you wear a school girl uniform (even though you're a guy) throughout the whole thing, it's time to bail.
[Photo via @omweekend]