Sexual tension is a "spark" — distinct from raw physical arousal or making out — that precedes and ignites attraction, and can be deliberately engineered in a short conversational window using an additive/subtractive formula:
Sexual Relevance + Uncertainty + Validation + Investment − Resistance/Rejection = Sexual Tension
Mastery means internalizing these five elements well enough to generate tension-creating lines spontaneously rather than reciting memorized ones — canned lines are "training wheels" for the underlying concept.
Sexual Relevance — the girl must perceive you as a potential sexual/romantic option, not a platonic conversational partner. Framing the conversation as man-to-woman (rather than sticking to neutral topics like weather or homework) signals it's socially acceptable for her to have a sexual thought about you — otherwise you default into the friend zone.
Uncertainty — a little doubt in her mind about whether she can "have" you. People don't value what comes too easily; introduce doubt rather than being fully secure/available. Related to Mystery Through Calculated Absence.
Validation — winning your interest must feel like an achievement or status win to her, not a given. Related to DHV: Demonstration of Higher Value and Status as Relative Standing (The Real Attractor Behind LMS).
Investment — her contributed effort/energy in the interaction, which increases psychological attachment via the commitment-and-consistency principle: people view themselves as congruent with the actions/effort they've already taken, so getting her to chase, tease back, or defend herself makes her rationalize stronger interest in you to stay consistent with that effort.
Resistance/Rejection (subtractive) — outright rejection of your frame or persona destroys sexual tension "like deflating a balloon." This is distinct from a shit test (a dismissive or testing response that probes the strength of your frame without fully rejecting it) — shit tests, when passed without backing down or getting reactive, function as a catalyst for more tension rather than an obstacle. See Push-Pull Teasing.
Canned lines are a developmental stage, not the goal — internalizing why each element works lets you generate tension-creating lines spontaneously rather than reciting scripts. See Charisma as a Trainable Skill (Reps).