Tus y tus

[Liam]

Hi,
I have come across the following Idioma española ( from Rusty)
"A perro viejo no hay tus tus"
I know that the common English equivalent is “You can’t teach an old dog new tricks.
However it is very interesting and also gives us some insight into Spanish culture to know the literal translation of the Spanish saying
Sometimes the translations are straight forward or the equivalent meaning in English is pretty obvious.
However I have found this one particularly tricky especially translating “no hay tus tus”
Besides the “your” meaning of tus I have read two others
1. tus, exclamation (a un perro),,,Good boy! Here boy!
2. Tus (sm) + modismo: “No decir tus ni mus”,,, without saying a word.
(Collins complete & unabridged English-Spanish dictionary)
However this really does not help me with the overall translation.
Further information ~ very welcome
Gracias
Saludos cordiales
Liam y Bracheion.