In brief
If someone states something and you think he/she knows nothing about what she is talking you can say 'bitch please'. In my opinion it's half of the sentence. If you want to complete it, it would be something like
'Bitch please stop'
'Bitch please, shut up'
You can use it if you feels like he stated something really stupid.
Sometimes ppl use it for this too. Let's assume that someone is explaining a situation and you know a situation far worse or far better than that.
Example (For a worse situation)
Let's take two men who are A & B
A - "It was raining a bit hard today morning".
Now let's assume B had experienced something worse. Now he can say
B - "Bitch please, it was raining cats & dogs"
Example (For a better)
A - "I have a Prado"
B - "Bitch please, I have a Lambo"
