The narrator tells us that he loves his best friend, and that he hasn't been in the tub with him since high school. He's been having sex with him in the shower, and he's had sex with her before, but this is the first time he has heard her moan in public. The narrator says that he'll never know that side of her that she's never known before. He says that she always twitches and grabs him, and this is how she gets sex.