Not all "friends with benefits" (heretofore referred to as FWB) relationships are made equally -- as one might expect when you "add sex and stir," as some researchers have framed the 21st-century not-so-romantic setup. A cornerstone of the millennial generation's "hookup culture," FWB relationships may come off as straightforward sex-minus-dating arrangements, but as anyone who's even flirted with FWBs knows, things can get complicated fast given how humans aren't so keenly evolved toward cleanly separating sex with a consistent partner from feelings toward said consistent partner.
To better understand the complexities within FWBs, a 2011 study out of the University of Arizona identified seven (SEVEN!) varieties of FWB relationships. Based on interviews with heterosexual college students, they itemized the following FWB categories: