"Button mash" refers to repeatedly pressing buttons on a controller or keyboard in a quick and uncontrolled manner, usually in video games. Full definition
Every combination of buttons does something different and while newbies can just button mash weak combo's, the game rewards those who learn all the different manual combo's with more damage done. (playstationlifestyle.net)
Speaking of which, the game is very much of an all - out button mash at some points. (engagedfamilygaming.com)
It may seem like some kind of frantic button mash, but it's anything but. (consoleob.com)