Physical mechanics are only half the battle. Research consistently shows that sex is rated as "better" when there is a strong emotional bond.
A romantic storyline is strongest when it is not the characters' only reason for existing.
: Send a flirtatious text or give a lingering kiss earlier in the day to build anticipation. 2. Prioritize the Build-Up (Foreplay)
Characters often connect because they fulfill a missing emotional or practical need in one another.