As she comes to the end of her poem of admiration for her husband she returns to his lips. His lips are the locus of sweetness with which she so desires to make contact once again, if only she can reconnect with her beloved.1
As in Song of Solomon 2:3, her description of him as a tree (Song of Solomon 5:15) and sweet-tasting fruit (this verse) belong together.2
16 His mouth is most sweet, and he is altogether desirable. This is my beloved and this is my friend, O daughters of Jerusalem.