Search this board for "MMF MFM" [Any of these words ...] and you'll get several hits, including some additional advice.  (Same search on General, Newbie and the NY Board will turn up more hits and general info.)
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In the case of touring couples (or solos with local friends), COVID might have changed regular travel or touring.  
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One more thing: MFM usually means that the guys don't interact too much, the F is in the middle. If it says MMF, that implies more but not exclusive MM interaction.  That's a rough guide, so if you are bi-curious, make sure that the party of the second part and the party of the first part have a clear understanding.  
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Good luck.

EDIT: Hay! You've been posting this Q for several years. I've even replied to you before. Have you had any success? How did it go? I mean that in the general sense, as in the usual problems: "NCNS" "Lost my deposit." Others might have more suggestions.

-- Modified on 7/31/2020 10:06:08 AM

Just to have the info "in one place" (this thread), take note of Daphne and Tyler who offer MFM and MMF services. They advertise on the Boston Ad board, e.g.,  
http://www.theeroticreview.com/discussion-boards/boston-ads-68/upscale-kinky-couple-available-for-mmf-or-mfmf-duos-6-23-6-30-49046

You've been asking about this for several years. Have you ever followed through? Let us know how things went. Are you really planning to follow through? Let us know how things go.