Someone mostly straight but occasionally open to same-gender attraction.
The whole word hangs on "mostly." Heteroflexible is for people who'd tick "straight" on any form without blinking, and then, every so often, feel a pull toward the same gender that just doesn't fit the box. Not a phase they're performing, not a dare — a small, real exception inside an otherwise steady pattern. Ritch Savin-Williams, the psychologist who put "mostly straight" on the academic map, frames it as an identity with its own weight, not a rest stop on the road to somewhere gayer.
Isn't that just bisexual? Technically the umbrella covers it — attraction to more than one gender. But heteroflexible carries a built-in weighting that plain "bisexual" doesn't: the emphasis is on the lean, not the balance. It's also not bi-curious, which implies wanting to try; heteroflexible experiments less and, more often, quietly already knows. Critics say the label feeds bisexual erasure — a way to enjoy same-gender attraction while keeping one foot planted on straight ground. Defenders say people get to name their own weather. Both can be true at once.
The experience is older than the word. Surveys keep turning up people who call themselves heterosexual and also report same-gender attraction or contact; one line of research clocks the "predominantly heterosexual" as the single largest slice of the sexual-minority pie. What's new isn't the desire — it's finally having a term that admits "mostly" without forcing it to mean "always."