1- Show the needle your the boss.
His horn(needle) prevents him from speaking, but he has discovered ways to work around it.
2- We can mix two different threads.
He is buckskin, therefore both black and gold. Could also refer to his mane, the tips are sun-bleached and therefore lighter than the rest.
3- The thread your using is a combo of two.
Another color ref, or possibly his personality. He is harsh and short-tempered around adult horses, yet is gentle and loving to foals, two completely different reactions.
Isn't it pretty?
In their first thread together, Demetrie thought his horn was cool/pretty.