The act of flirtation might well be a maneuver, or even a social 'attack', but I would suggest that the strength of wording of the aspect be tied to the 'magnitude' of the placed aspect (maneuver, mild, moderate, severe, extreme), and that a lasting crush would be solidly in the realm of consequences.
Maneuvers only last about one scene, at most, and generally you have to screw up rather badly to squelch a crush within the same scene that it emerges.