The spelling of the word "b bs" may seem unusual, but it follows the rules of English phonetics. The word is pronounced with a short "u" sound followed by a voiced "b" and a voiceless "s" sound. The two "b" letters indicate a voiced bilabial plosive, while the letter "s" represents the voiceless alveolar fricative. The use of doubled consonants in English often serves to indicate a short vowel sound, as is the case here.
The word "b bs" is an abbreviation for a vulgar slang term that refers to falsehoods or nonsense. Its etymology can be traced back to the early 20th century. The term most likely originated as a euphemistic way of saying "bullshit", which itself has a long history as an expletive meaning lies or exaggeration. However, due to the offensive nature of the original term, "b bs" became a more acceptable alternative in informal conversation and writing.