It's a translation of meaning from Shakespeare.
A similar variation comes from SparkNotes:
Lead us, monster; we’ll follow. I wish I could see this invisible drummer. He really plays well.
As a modern idiom, lays it on (or lay it on) it means something specifically different:
: to speak in a way that is exaggerated and not sincere
// You should compliment her cooking but don't lay it on too thick or she'll know you don't mean it.
// He laid it on pretty heavily and pretended to be interested in what she said.
But translations are seldom word-for-word literal, and they are somewhat open to interpretation. (Many foreign-language classics have multiple translations.)
In this case, the idiom as we know it today may well not have existed in Shakespeare's time—or lays it on may have been thought of as goes all out and used in a positive sense rather than the somewhat deprecatory sense it has now.
But at least in the context of the original, he's very good seems like a good translation—and certainly better than he's exaggerated and insincere.