Finally Lenur (Lenur) in Russia wants to know the meaning of the phrase " to lay it on thick." If someone says, " He's laying it on a little too thick, " what does that mean?

最后，俄罗斯的列努尔（Lenur）想知道“to lay it on thick”这句话的意思。如果有人说，“He's laying it on it too thick”，那是什么意思？