The most curious use, to me, of this word comes from Britain. In this case, “bitch” refers to human females, but not necessarily those of ill repute, and extends from them to something associated with them. This usage, in fact, refers to the more socially popular ladies who gather together to chat at a tea party, or bitch party as it was called circa 1880. This bitch party was composed of females of the species (wives) who would spend their afternoons discussing topics of importance to them. To the husbands, this was a gathering of bitches who spent their time together bitching while drinking a typical drink of bitches, tea. Perhaps through guilt by association, Cambridge University slang from 1820 to about 1914 called this drink – tea – “bitch” (Partridge 1966:57). Furthermore, to pour out tea was to “bitch the pot” (Partridge 1950:210), and one who poured the tea was said to “stand bitch”. “Stand bitch” in the late 18th and 19th centuries actually meant not only to preside at tea but also to perform any other typically female duty (Partridge 1966:57) or, in short, to behave like the female of the species. Metaphors accounting for these tea-time terms are not apparent to me and I do not think metaphors are responsible for these meanings. Instead, I think that the terms came about through their associations with the social function of tea and ladies at tea parties and shifted to the other meanings.
from Collins, C.A. (1984). ‘Bitch: An example of semantic development and change’