Here's a breakdown:
* "May place your lips upon my posterity": This refers to the idea of leaving a physical imprint on the future. The act of kissing is symbolic of leaving a tangible mark, just like a kiss on a cheek leaves a physical sensation.
* "And kiss it": This emphasizes the act of imparting something special, a blessing or a legacy, on the generations to come.
The phrase evokes a sense of legacy and immortality. It's a way of expressing the desire for one's actions and values to have a positive and enduring influence on the world, even after they are gone.
It's important to note that the phrase has a somewhat archaic and formal tone, suggesting it may have been used in a historical context or a literary work.