I found on the Internet the history of the emergence of Russian insults. In particular:
B is
The word is derived from the ancient Russian verb bladyti, meaning "to deceive, to blaspheme". It is believed that this Russian word is a relative of the English word bladdeg - "bubble" and "pustomel", as well as the famous American blah-blah-blah - "empty talk". The modern meaning of the word - most likely, the result of semantic mixture with the word "blud", derived from the ancient Russian bludity - "bludge." Until the 18th century, the word “b...” was used in literature without restrictions.
I tell all this to my wife, concluding that b...y is just a missing girl!
She listened to me silently and after a two-second pause said:
Every B by compass. No matter what they wandered!