Mm'ing 

Mm'ing is when you and your partner endure sexual intercourse with eachother with both of you resulting in an orgasm

I want to mm you
Mm'ing

Mm'ing by Hickman&Burton January 26, 2015

MM'ing 

Slang for "making memories." Attending an event or performing an action with the conscious intent of creating a memory from said event or action.

"What are you guys doing?" "We're just MM'ing over at Roy's house with fingerpaints. You should come!"

MM'ing by jsasfe June 2, 2013

mm'ing 

The act of fouling up an internet forum by posing useless hypotheticals, drudging up dormant shitstorms and posting innumerable polls with no conceivable purpose, merely to see your name in lights.

eugene: "What the hell happened to this forum?! It's like half of you are are mm'ing."

mm: "Poll: do you think this forum has gone downhill since my increased presence here, or not? Or does it not matter in the least? In any case, please respond. Or not."

mm'ing by Gunther Bunky January 24, 2009