v. When a proficient piano player is able to hit several groups of notes at different ends of the piano, sometimes in a sweeping motion, at a very fast pace (during an Allegro piece).
"Yeah she's a really good piano player".
"OH YEAH do you remember in the last performance she was absolutely hand-mopping those keys!"
Cleaningsomething with your tongue. Usually used in a sexual context. It is named this way due to the way the tongue moves being similar to how a mop moves when used for cleaning floors.