[Mettaton is glad that Fi isn't really pushing him for being so intoxicated. At least, she's not doing it in a way that makes him regret what he's done. Deep down he knows his happiness is temporary, but...if it can last for even a short while, he'll take it.

He needs the distraction. Oh, and speaking of distractions...]

Oh, thank you very much!! I"m quite pleased with both myself!! Especially Papyrus, he's such a darling and he's put up with me so much!!! It really is the most I can ask for!

[...He decides to omit the fact that Toriel had "helped" him come to the decision that the secret of his origins wasn't worth hiding anymore. It still bothered him to talk about, but without inhibitions, it was simpler to do.]