I'm Not Your Mommy 2.

Lexi is determined to seduce her young but very nervous accountant. When he fumbles her pass, Lexi takes charge, putting his hands on her tits. She then makes things even clearer by shoving his face into her warm, wet pussy. Leana's mom has caught these step-siblings fooling around so she sends them to Dr. White who encourages them to embrace their desires. They're nervous at first but decide that fucking in front of the doctor might be therapeutic.