There is plenty of room to allow for the tubist/euphonist to incorporate auxiliary instruments into their performance. Examples include added percussion (the author has personally performed with a kick drum and a whistle in a new piece for tuba), various “toy” instruments like the kazoo and train whistle, and electronic instruments.
The ultimate concern with this technique is in making sure that the performer has adequate time to switch between or add in the auxiliary instruments.
Since this technique involves adding things not related to tuba or euphonium performance, there may be some hesitance on the performer’s part. It is highly recommended that the composer wishing to utilize this technique first check that the intended performer is comfortable with doing so.
Any clear and consistent method for notating this technique is acceptable. Given the auxiliary nature of the technique, it is advisable to keep the extra notation separated from the bulk of the musical gestures, either via a separate staff or directions above/below the main staff. The provided example demonstrates this notation method, and in the author’s experience, this works very well and is quite easy to learn.
Advanced to Professional
Works to consider (bolded titles are particularly representative examples of this technique)
Hommage à Brian Ferneyhough – Claus-Steffen Mahnkopf
Tuba Mirum – Trevor Wishart
And What Rough Beast…? – Marc Satterwhite
Code Fragments – Carter John Rice