Meghan Trainor and New Fiance Daryl Sabara Still in PDA Mode

Meghan Trainor and her "Spy Kids" star fiance are still basking in the glow of their recent engagement -- y'know that period where a simple stop on a street corner means let's make out.

Meghan and Daryl Sabara puckered up Wednesday during a stroll around WeHo. We'd say the smooch left 'em both feeling pretty good -- they walked off giggling, hand-in-hand.

As we reported ... Daryl got on one knee for Meghan just a couple days before Christmas, which also happened to be her 24th birthday.