Merthin 

Muff diving on a woman to give her a second orgasm AFTER you have already filled her full of your baby batter.

I was ready to go to sleep but she was insatiable! She grabbed me by the ears and made me give her a Merthin.

Merthin by kenfollet April 19, 2010

Merching

Doing paid to posts on Instagram.

Now that Oliver's got 100k followers, he's gonna be merching the fuck out of his IG.

Merching by 1dead June 22, 2019

Crystal Methin' 

Crystal Methin' = a word commonly used by chavs to describe something as good. Used by MC Devvo. Refers to methamphetamine, a highly potent illegal drug.

Woah, dik'ed that was fuckin crystal methin'!

Crystal Methin' by Matt Scheepers August 29, 2007

merphing

screwing around in altogether unlawful or jovial shinanigans

Girl: What are you idiots doing?
Boy: just merphing around. . .

Girl: What?
Boy: sorry, i mean i am participating in unlawful shinanigans, gosh

merphing by 13speakers October 18, 2009

methinks

Archaic Verb. A surviving old-English dative construction of "it seems to me" where "me" is the indirect object. Sadly, abused by people who make special trips to Pinkberry.

past tense: methought.

They talk about their Pilgrim blood,
Their birthright high and holy!
A mountain-stream that ends in mud
Methinks is melancholy.

methinks by maniacal engineer September 11, 2010

Mething Around 

Messing around while high on Crystal Meth.

The house became a disaster, from Dan & Jessica mething around.

Mething Around by Steadybeat August 8, 2020

mirthing

(v) the act of quietly and secretly enjoying a private joke with yourself, to the point of abdominal pain. (that would be why it rhymes with "birthing").

Chris was mirthing to himself in a corner, giving him the acute appearance of an individual in need of a straitjacket.

mirthing by the.kanguru March 31, 2011