The Smell of His Cologne
The senses bring back memories in various ways. The sense of smell especially can inhibit one's mind and trigger emotions of childhood times, holidays with family, or even the scent of your one true love.
Rachel and Matt share a common love for the fragrance of cologne she had purchased for him called Blissful. The smell worked like an aphrodisiac for Rachel. After Matt dies tragically, the cologne is used to reunite the love of another man, at Matt's request; his best friend who also had a history with Rachel.