Silvia is overheard telling her friend on the phone that her husband thinks anal isn't cheating, so she would like to take him up on that. In fact, she wouldn't mind getting done by her stepson Jay.

Jay hears this and convinces her to give him her ass. Before that, Silvia needs to warm him up with a blowjob, he needs to warm her up with cunnilingus
and then by his penis in her pussy. When he questions this, she tells him it's okay as he needs to warm her ass up.

A lot of coitus, a lot of anal, no dialogue except the obligatory moaning and groaning interspersed with oh fucks, oh my gods and oh yeahs.

The only dialogue is at the beginning when they talk about it, and at the end when they agree to keep it a secret.