The word is actually balderdash. It is an old-fashioned word, and used now to be humourously dismissive, to call something nonsense.
Yes, it is completely non-vulgar, and if used, gives the impression that what is being dismissed as nonsense is so ridiculous, it is laughable.
BS runs the gamut, from a friendly tone of voice and a smile = somebody's exaggerating, or you think what they're saying is wrong (such as trying to tell you their football team will beat your football team next Saturday) etc; to furiously angry, when it would be, 'that's f*****g bs'
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