ACT ONE, “give me my sin again”
The term “sin“ implies that he knows his family society, and God will be disapproving, and it is thus unscrupulous. The word also connotative temptation showing that he is willing to fey them.
He extends Juliet’s metaphor; “let my lips have the sin again“ they should be romantic, but the romance is dumped by the impending sense of doom.
He subvert the excitingly seductive connotations of kiss, turning it into a grim enchantment of Romeo’s fate.