One of the most antiquated stereotypes about bisexual people is that they're always DTF and without question embrace polyamory. "Unicorn" is a term used to describe a bisexual person (usually a woman) who sleeps with heterosexual couples. In online dating, unicorn hunting is when a straight, coupled woman user writes that she's "looking for women" — not genuinely looking for someone to get to know romantically, but only for someone interested in a threesome with her and her boyfriend or husband or whoever. Of course, they don't mention that tiny detail until later. No one is saying that threesomes are bad. Reddit users who have experienced this mention that they don't have a problem with "ethical non-monogamy" per se. What they do have a problem with is being tricked into it. Big difference.