Line 38 I'll be a candle-holder . . .
a phrase still very common in Rome, with reference to playing the odd man out: arèggere 'r mòccolo
Lines 92-3 This is the hag, when maids lie on their backs,
That presses them and learns them first to bear
see the devil called incubus, like in Fuseli's two paintings titled Nightmare; here however the odd thing is that Queen Mab acts as woman on woman. But especially, in the play, the "maid lying on her back" is Juliet: Scene iii, lines 40 ff.
Line 100 Which is as thin of substance as the air
like humankind, according to Macbeth's well-known definition
Line 106 [Juliet] Then have my lips the sin that they have took
the "original sin" is transmitted from him to her, the opposite of Adam and Eve
Line 108 You kiss by th' book
handbooks were a Renaissance mania
Line 136-7 Too early seen unknown, and known too late!
Prodigious birth . . .
Juliet apparently paraphrases St. Augustine's famous sentence, "Late have I loved you [God], beauty so ancient and so new!" And "prodigious," though meaning "ominous" in this context, also mirrors the theological parlance referring to the birth of Christ.