Monogamous Friends with Benefits. .
So you're having sex with a friend but only that one friend. Generally this is an agreed upon situation by one married person and one single person. The married person may or may not be having sex with their spouse. The single person feels better if it's M-FWB. Otherwise, they'll assume you're banging half the city.
"I'm having sex with Cindy from accounting"
"She knows your married, right?"
"Yeah, it's a MFWB thing so she's cool with it"
by I won't tell. March 21, 2018
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Made Fart With Butt. The act of making a fart with one’s butt.
As the terrible aroma began to fill the room, it became abundantly clear that Alex had indeed MFWB (Made Fart With Butt).
by Dr. Corn September 6, 2021
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When you "Make Fart With Butt".
I MFWB'd so hard next to that girl.
by jakegrealg July 31, 2020
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