In sync
You can tell when the lovers are in absolute sync by the way each of them seems to always know what another one wants at any given moment. Just look at Lily and Edward! They have such a great chemistry together cuz they love the same things in sex. Whenever Tina feels like getting licked to orgasm Edward is ready to work his tongue on her clit for hours and when she's in a mood for anal sex he's ready to give her ass all the fucking it can handle.