The guy is lucky with his sister - she is a nipple. She's ready to open her mouth for him to stick it in her. Apparently she serves him regularly, because he no longer feels affection for her, but fucks her like a street whore - rough and bold. However, she seems to like this treatment.
The redheaded chick has it written all over her face that she's a nipple. Her eyes have seen a lot of dicks. And of course her girlfriend helps her swallow. The redhead is especially good at sucking her balls - she's itching for her own!