As Charlie’s efforts come in bursts, each pause in his rhythm is a tease, both for him and for the listener. We hear his pleasure build and build yet each time he halts, delaying his climax until the timing is right.
With a clean body and a dirty mind, Ethan has some extras to attend to as part of his daily routine, finishing up rinsed and refreshed.
As Oscar performs a little self-love for our microphones (and himself), pay attention, not just to the slick sound of his fapping, but to all the subtle sounds of his arousal. It may just have an empathetic effect.