Ralph walks in on Meg changing. We see her from the shoulders up and brief side boob (no nipples); she smiles, having secretly planned the whole thing, though Ralph is embarrassed by it.
Meg makes repeated unwanted comments about Ralph being "sexy" and grabbing his shoulders, joking that she'll "steal him away". She says all this in front of his wife.
Meg decides to have Annie's home pregnancy test mounted in a frame; this creeps out Annie and Ralph as they try to decide whether to keep it as a gag gift or throw it out.
Meg wears a shoulderless, low-cut black dress in a basement scene.
Ralph and Meg passionately kiss in a darkroom. Ralph puts his hands on Meg's waist. This turns out to be Meg's fantasy; she then tries to kiss Ralph for real, and he backs away, repulsed.
Meg shouts about coming on to Ralph and not being a "homewrecker".