The moment just before when two characters are about to kiss.
The characters' mouths should be in close proximity to each other. Often there will be head tilting, blushing, chin grabbing, eye closing (alternatively, direct eye-to-eye contact) and other such bodily cues present.
Not to be confused with incoming kiss, which is an incoming kiss from the character to the viewer.
Depending on how ambiguous it is, this tag may overlap with after kiss.