Srimad Bhagavatam Canto 07, Chapter 05, Text 46

SB 7.5.46

vartamano ’vidure vai
 balo ’py ajada-dhir ayam
na vismarati me ’naryam
 sunah sepa iva prabhuh
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Although he is very near to me and is merely a child, he is situated in complete fearlessness. He resembles a dog’s curved tail, which can never be straightened, because he never forgets my misbehavior and his connection with his master, Lord Visnu.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
The word sunah means “of a dog,” and sepa means “tail.” The example is ordinary. However one may try to straighten a dog’s tail, it is never straight but always curved. Sunah sepa is also the name of the second son of Ajigarta. He was sold to Hariscandra, but he later took shelter of Visvamitra, Hariscandra’s enemy, and never left his side.
Srimad Bhagavatam Canto 07, Chapter 05, Text 45
Srimad Bhagavatam Canto 07, Chapter 05, Text 47