The Narrator
The narrator of the poem is a man speaking to his mistress, as the title of the poem implies. What it might not imply, however, is the bluntly sexualized banter the narrator uses to coax his mistress into bed. He seems to be entirely shameless, comparing her to an angel and a beautiful figure from Greek mythology and referencing such sources as God, Muhammad, America, and midwives in his varied attempts to convince her to strip off her clothes. He seems to have only one thing in mind, and he appears pretty determined to get it – he even takes off all his clothes and asks her to follow suit.
The Mistress
The subject of the narrator's poem, the mistress is described in great detail. She is clearly quite physically beautiful - the narrator spends several lines slowly describing what he anticipates about each part of her anatomy. From the narrator's repeated efforts, it seems she is a little shy about removing her clothes and climbing into bed with him, an inhibition of which he seems more than happy to relieve her. The narrator tellingly only describes her physical aspects - we unfortunately get no descriptions of any of her other characteristics.