Something is translating weird here. How is bitch the same as slut? That is what it is saying, right? Bitch usually means a female who is ruthless and inconsiderate of others, a real jerk.
And how are they using "son of a bitch"? Normally its used to mean a foul jerk, someone with low morals, little consideration for others, and sometimes has a hint of pathetic implied in it. Usually used as a insult. I don't get at all how it's being used here. Son of a bitch, and bitch, generally have the same usage in american english, except bitch implies stronger and is sometimes embraced as a self label and of course bitch is used exclusively with females. The exception is the slang of making someone your bitch, which implies ownership of that person, like a slave, often with sexual implication, and is almost always used this way only with males.
Well I am sure the meaning in the comic is far removed from these usages, but its confusing, the jokes lost on me.