Trivia: It is unclear whether Jack is Oggy's cousin or friend, but in the episode "Love and Kisses" (S2E81), it was shown that Jack instantly fell in love at first sight with Monica (Oggy's Sister), which tells us that Jack is indeed Oggy's friend. Making him Oggy's cousin would be considered as cousin marriage.
Trivia: Throughout the whole series, Oggy's house contains various disproportional rooms inside of it. For example, the living room inside of the house is literally twice the size of the house alone. What's hilarious is that Oggy used the living room only to watch TV.
Answer: It sounded like he was laughing, but he actually wasn't. Actually, he was getting nervous because he got gruesomely injured throughout this entire episode, and this was the last straw for him.