This is a song about performing innocence lost rather than actually losing it. Addison catalogs every move she makes—lipstick on his chest, sitting on his lap, writing her name—like she's directing herself in a music video. The repeated command 'say you love me' is never answered because she never says she loves him either. This is summer as aesthetic, not feeling.
My boy's a winner, he loves the game / My lips reflect off his cross gold chain
She describes him like an accessory. The detail that matters is how her lips look reflected in his jewelry, not what he says or does. She's cataloging the visual, staging the scene.
Sitting on his lap, sippin' Diet Pepsi
Diet Pepsi is the fake version of the real thing, and she puts it at the center of 'summer love.' The whole song is the lite version of passion—all the moves, none of the mess.
I write my name with lipstick on your chest / I leave a mark so you know I'm the best
She's not marking him as hers. She's branding him with proof she's the best at this performance. The mark is for an audience that isn't there, evidence of a skill demonstrated.
Say you love, say you love, say you love me
She demands he say it three times per chorus, but we never hear his voice. He never actually says it back. She fills the silence with her own performance of what losing innocence is supposed to look like.
Losing all my innocence in the backseat
She repeats this eight times, but the innocence sounds already gone. You don't announce you're losing innocence while you're losing it. You announce it when you're playing the role of the girl who's losing it.
What sticks is the gap between what she says is happening and what's actually happening. She thinks she's narrating a seduction. She's really narrating a photoshoot where she already knows all the poses. The backseat isn't where innocence gets lost. It's where she performs having lost it, alone.