Scent Synergy Share definition Flag Using various bath products of the same marketing line in order to avoid a conflict of scents. I have the whole Old Spice: Swagger line. The shampoo, the soap, the deodorant, and the cologne. Complete and total scent synergy. Scent Synergy by thebetterfriend2 August 13, 2014 Get the Scent Synergy mug.