Stewie, what the hell happened? Oh well, shortly after you lef...
Brian: Stewie, what the hell happened?
Stewie: Oh well, shortly after you left, da Vinci's girlfriend showed up. So I injected her with my DNA.
Brian: You had sex?
Stewie: No, I put my DNA inside of her.
Brian: Right, you had sex.
Stewie: No, what are you not getting? I put a sample of my DNa in a syringe and I injected her on the staircase, on the couch, and on the balcony.