I enjoy that scene.
Spoiler:Especially when Carla was on the top. She surely enjoys that "in-and-out" manuever. Note that she was moving her body very slowly yet elegantly, fully bloom the scent of a woman with a shapy body. I am sure that itching feeling inside the tunnel and the squizy sound od stroking the lubricated 'cold' rod. Don't forget Carla noticed that Lucas is cold after the park incident.