Andrew Marvell’s "To His Coy Mistress" is constantly on the move between images of freedom and images of imprisonment. As we read why the speaker feels trapped, and how he thinks he can get out, we feel the need to examine the freedoms and confinements of our own lives. The poem can feel claustrophobic at some moments, but, at other moments, we feel all our confines crumble.
By trying to make the mistress do what he wants her to, the speaker tries to take away her freedom.
Sex in the poem is a metaphor for the writing process – what the speaker really wants is enough time to write, and, hopefully, to create a poem that will last longer than he will.