i feel like optimus and starscream are both criers during sex, but on opposite ends of the spectrum.
optimus cries because of the emotion of it all. when he's truly in love with someone, he can't help but show it a bit, even if it means shedding a few tears. he's not a loud crier either, he doesn't like to draw attention to it, but you'll see him wipe away some tears as he smiles at just how wonderful his partner is, and how lucky he feels to be with them.
starscream, on the other hand, absolutely wails from overstimulation and being unable to properly articulate how good it feels to get his back blown out.
