What does this line mean: "Is this a prologue, or the posy of a ring?"Shakespeare's Hamlet

Just as Act III, Scene 1 of Hamlet
has involved every major character in a duplicitous act, with the exception of Horatio
and Laertes.  Now, in Act III, Scene 2, there is duplicity; however, whereas the first
scene contains duplicity that it seemingly good, the intent is evil, the second scene's
duplicity is apparently for evil designs, but its goal is
good.

In this scene, Hamlet has altered the purpose of the
Dumb Show of the play that the actors are soon to perform.  For, he has this provide the
synopsis of the play whereas usually the Prologue does this.  When the actor appears who
is the "prologue," he speaks briefly,

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For us, and for our
tragedy,

Here stooping to your
clemncy,

We beg your hearing patiently.
(3.2.131-133)

Upon hearing
this, Hamlet asks, "Is this a prologue, or the posy of a ring?"  meaning is this the
prologue or simply a verse.  There is wordplay with poesy here in
the word "posy" that Hamlet uses.  For, it is the idea of a poem being a flower; such
short verses were engraved inside a wedding ring like the one Hamlet had planned to give
Ophelia.  His remark, then, falls in line with the other sexually suggestive and
derogatory remarks to Ophelia, whom Hamlet now believes to be a courtesan of
Claudius.