(strictly) vonce

[Mullins, Bill]

 l
>
> I believe the writer is referring to "vantz", Yiddish for
> 'bedbug' (German is "wanze"). I know that jazz musicians have
> borrowed some Yiddish terms (e.g., "schmaltz"), but it
> doesn't seem plausible that "doing the vonce"
> means "doing the bedbug". The "bedbug" derivation doesn't
> really work for the other senses of "vonce" either. (But who
> knows? Maybe Lester Young heard a Yiddish speaker calling a
> mischievous kid a "vantz" and he just liked the sound of it!)
>

German for "tail" is Schwanz, I believe. Perhaps relevant?