What do we learn from "v'Chichech k'Yayin ha'Tov"?
Rashi: Be careful with your answers, that they be like good wine.
Seforno: At a time of Hochi'ach (when a Chacham seeks to prove that he is correct), it should be like good wine, that the palate benefits 1 from it.
Malbim (Melitzah): Chichech is internal speech with Chachmah, like above "Chiko Mamsakim" (5:16). Yayin ha'Tov in this Sefer is Ru'ach ha'Kodesh. He accepts on himself that if he will live, he will engage only in Torah, Chachmah and Mitzvos, and seek Kedushah and knowledge of Elokim.
Malbim (Mashal): Your palate is like good wine, which delights the heart. Until here ha'Melech Shlomo spoke.
It seems that the text of Seforno should say 'Yeheneh', and not 'Yihyeh' (PF).
Why does it say "Holech l'Dodi l'Meisharim"?
Rashi: I am careful to answer them that I will stand in my Emunah. My palate will go in front of my Beloved for love of straightness, which is from the heart, and not with guile.
Seforno: The intent should be to find grace in the eyes of my Beloved, in seeking the Emes, and not for the sake of victory.
Malbim (Melitzah): The Nefesh answers, I will not return to the king (the heart and body), for I go to my supreme Beloved. I will return to my abode in Shamayim. I go to what is straight - Elokei ha'Ruchos, the source of what is straight and good.
Malbim (Mashal): The beloved answers, I go to my beloved. This wine will not be for you, rather, for my beloved, the shepherd. Do not ascend to my height, for I will go to my beloved, and I will be to him. He is straightness. I.e. he depicts straightness itself. He is full of straightness and Tzedek.
What do we learn from "[v'Chichech k'Yayin ha'Tov...] Dovev Sifsei Yeshenim"?
Torah Temimah citing Yevamos 97a: Just like a Kli in which grapes are placed until they get warm, once one puts his finger on it, it moves. Likewise, when people say teachings of Chachamim in their names in this world, their lips move in the grave.
Rashi: Good wine moves the lips of the sleeping (when one puts some to his lips). Also my ancestors in the grave will rejoice and thank for their portion.
Seforno: He will mention the words of earlier Chachamim, and add to them as is proper for each later one.
Malbim (Melitzah): Now, at the time of death, Shlomo is Goses (close to death). His lips already sleep the sleep of death, and say what follows.
Malbim (Mashal): Also when my lips sleep, they say [the following] due to my great desire and habituation to mention my beloved.
