Keyboard Mashing is, essentially the result of someone mashing their keyboard in certain circumstances. Such as in times of frustration, anger, boredom, an attempt to relieve stress or due to a violent spasm in the typist's hands and arms. This generally occurs in chatrooms or on chat programs, such as MSN, IRC, AIM etc.
RandomMSNnick #1 says:
Hey dude, what've you been up to today?

RandomMSNnick #2 says:
fghjfghjas da874r

RandomMSNnick #1 says:
Been that kinda day, huh? Ain't seen you Keyboard Mashing in a while..
by Iron_Demon October 8, 2005
The greatest possible expression of frustration short of bestial snarling.

Also the only word in the English language that can legitimately include numbers and be spelt any way you please.
The Keyboard Mash in use:

"Why are you so adsfl;kjqearlf;jking stupid?!"

"389uy4r89w34yhegoiahrg9024t90"

"asdf;lkad;glaf!"

"&hy&%^78Hn"
by Jessica Ellen September 5, 2008
The most sophisticated way of expressing a mind fuck on instant messaging. Expressed after viewing something that just makes you go "heiucrwy89lq39rlqtvy8huidhjszfaiuehwu9lhjktvu4 hq3atw8bhvj,2qioy78" or similar. Mostly expressed after viewing such things as 2girls1cup or goatse.
keyboard mash: heiucrwy89lq39rlqtvy8huidhjszfaiuehwu9lhjktvu4 hq3atw8bhvj,2qioy78
by mb500 December 17, 2009
when someone finds something funny and replies with random keyboard mashing rather than saying lmao or lol to show they're amused
mostly gays, preteens, or tumblr users use this tactic (or sometimes all three)
Gail: yo i fell down the stairs again
Sara: gGgHDGGDHShhhhdgdskskKDH
Gail: what the fuck was that
Sara: gay keyboard mashing
Gail: oh
by Get yeeted on October 15, 2018
The act of participating in "cyber-sex", that is the depiction of sexual content through the medium of a typed conversation on an internet chat room or online role-playing game. A very common occurrence in MUDs or anonymous chat sites, roleplaying as a person other than oneself is expected though not strictly mandatory. Masturbation involving one or both parties during the event is not unexpected.

While performed inside of online roleplaying games, it is not uncommon for the player characters to form a relationship within which the characters routinely cyber-sex each other as if they were in a "real life" relationship.

Many times in these relationships the players behind the characters will form emotional romantic bonds, possibly culminating in a romantic relationship outside of their cyber-sex medium. Just as often however are people fully capable of forming zero emotional connection with their online partners, even despite the heavy romance between their characters.
I logged on like it was going to be a normal day but when I saw my character's wife just crafted a new sexy dress we started mashing keyboards like there was no tomorrow.
by Papa Dwarf September 4, 2016
Keyboard mashed
Very useful to confusing friends into thinking you've had a stroke.
For example:
"Dude you ok? why'd you say that in chat"
"I Keyboard mashed"
by Yermy May 11, 2020