So, in classic Metaphysical Poet tradition, Donne doesn't make anything super-explicit, but it's hard to read this poem without noticing some sexual overtones. "O'erthrow me, and bend Your force" and "[I] labour to admit you" are examples of moments that carry sexual weight.
Plus, the final line of the poem is hard to ignore: "Nor ever chaste, except you ravish me." The speaker seems to try to give a more specific flavor to his demands here at the end of the poem. How about this: in struggling to make what he really wants concrete, the speaker finally admits his thoughts through the entire poem – the closest he can come to describing what he wants from God is through the metaphor of being ravished by God.