To me, polyfuckery is just a silly term to contrast with polyamory. For instance, if your rules with your partner are that you can sleep with whoever you want but you can't fall in love, I'd call that polyfuckery, and I'd probably only use that term in order to directly contrast with polyamory. For instance, "We engage in polyamory but without emotions allowed!" "Ok, no, amor means love, what you're doing is polyfuckery."
So I'm not sure it has an independent definition, I think maybe it exists only in counterpoint.
I think of swinging as being a specific community and type of lifestyle that's focused on couples and sometimes bi females (lesbians, bi dudes, single dudes, gay dudes, and transsexuals don't seem to be invited to the swinging party, so to speak? am I mistaken about that?), characterized by sex for fun, sometimes with warm feelings, but no real independent dating/relationships. In contrast, polyfuckery, like polyamory, seems to me to be, in connotation, less limited in terms of gender, orientation, and configuration.
The major players. Me, 30ish bi female. Gia, girlfriend of 4+ years. Clay, boyfriend/dom. Davis, ex/friend/"it's complicated." Eddie, roommate & fwb.
The supporting cast. Eric, Gia's husband. Bee, Gia and Eric's toddler. Dexter, Gia's lover. Helen, Eric's lover. Izzy and Nikki, Clay's partners. Liam, Eddie's husband.