>>89330954you see, the humour is derived from the juxtaposition of patrick's advice for light conversation only for immediate tonal whiplash with spongebob screaming about pregnancy, an often heavy and serious topic. further humor can be extracted from the follow-up panel where patrick comments about cardboard manufacturing, a topic that certainly wouldn't be considered "light or casual" either, meaning spongebob was never on track to begin with. hope this helped!
