Possible interpretations are 1) literal, the lover reaches into the house through a hole in the door in order to open the door or 2) euphemisic, they have begun to make love. (See: [[rc://en/ta/man/jit/figs-euphemism]])
This phrase refers to the man whom the woman loves. In some languages it may be more natural for her to refer to him as "my lover." See how you translated this in [Song of Songs 1:13](./12.md). Alternate translation: "My dear one" or "My lover"