Based on the message, your friend is referring to Lisa's cat (Katze in German) giving birth to 3 kittens (3 Junge). The key details: - Lisa, presumably your mutual friend, shared on Instagram that her cat had babies - Die Tatze refers to "the paw" which is a common way to affectionately refer to a cat in German - 3 Junge means 3 babies/kittens So your friend is excitedly telling you that Lisa's cat had 3 adorable kittens. The appropriate congratulations would be to congratulate Lisa on her cat having 3 new kittens.