There is no particular phase to describe it as per my knowledge. It's usually known as Triangle Player.
e.g.:
John Deacon of the rock group Queen assumed the role of a triangle player during the band's live performances.
A person who plays a musical instrument for a living is typically referred to as a musician. Musicians may perform solo or as part of a group, and they often specialize in a particular instrument or genre of music. Some may also compose or arrange music in addition to performing.
It matters which brass instrument. Someone with a Trombone is a trombonist, someone with a tuba is a tubist, and someone who plays a Trumpet is a trumpeter. It's all very complicated.
No, that is why they call it a beginner band.
A person who plays the bugle is typically referred to as a "bugler." Buglers often perform in military contexts, ceremonial events, or musical ensembles, using the instrument to signal commands or provide music. In some cases, they may also be called "horn players," but "bugler" is the most specific term for someone who plays this particular instrument.
An alphornist is a person who plays the alphorn - a long, curved horn used by mountain-dwellers in the alps, originally to call cattle but now as a musical instrument.
A "harmonicanist" is what a person who plays the harmonica is called.
A person who plays the piccolo is typically referred to as a "piccolo player." In orchestral settings, they may also be called a "piccoloist." This term highlights their specialization in playing the piccolo, a small woodwind instrument that produces high-pitched sounds.
Call and response is where either an instrument plays a melody and the singer echoes it or vice versa.
A person who plays Scrabble is called a Scrabbler. (unofficially)
"Soloist"
Someone who sings is typically referred to as a "singer," while a person who plays an instrument is called a "musician." If they specialize in a specific instrument, they might be identified by that instrument, such as "guitarist" or "pianist." Collectively, both singers and instrumentalists can be considered performers or artists in the music field.
A drummer or percussionist plays the drums.