symbol – n. something that stands for or suggests something else by reason of relationship, association, convention, or accidental resemblance; especially : a visible sign of something invisible <the lion is a symbol of courage>
affair – n. a romantic or passionate attachment typically of limited duration
euphoria – n. a feeling of well-being or elation : euphoria – adj.
tandem – n. in partnership or conjunction
dopamine – n. Biochemistry : a compound present in the body as a neurotransmitter and a precursor of other substances including epinephrine, acting within the brain to help regulate movement and emotion
to be smitten with someone – slang expression to be captivated and strongly attracted to someone <He was smitten with her beauty.>
circuit – n. a neuronal pathway of the brain along which electrical and chemical signals travel
erotic – adj. of, devoted to, or tending to arouse sexual love or desire <erotic art> : strongly marked or affected by sexual desire