Sandra Luberc and her stepbrother Tyler Nixon meet Julia Ann at a doctor's visit. Tyler goes first, dropping his pants so that Julia can take a look at his penis to determine whether he has overcome his problems with premature ejaculation. Next up it's Sandra's turn to have her annual exam. Just the sight of his stepsister gets Tyler rock hard. Julia decides to take action.
After getting Tyler naked, Julia encourages Sandra to rub Tyler's cock and then to suck it with slow strokes. Any time Tyler feels himself getting close to cumming, Julia hits him just enough to distract him from his pleasure.
When Tyler is ready to graduate to full on sex, Julia helps make him comfortable on the exam table so that Sandra can mount him in reverse cowgirl style and start riding him. As Julia helps to guide the stepsiblings in their exploration of each other she slowly sheds her clothes so that her enhanced big boobs hang free with rock hard nipples.
Now that Tyler seems to have overcome his problem completely, things can get really fun. Sandra gets some lessons on licking Julia's landing strip pussy, and then the girls form a double vagina stack with Sandra on top so that Tyler has his choice of tight holes to fill and fuck.
Tyler gets to show off his mettle on Julia when she lies down and spreads her legs for his hard fast thrusts, and once he's proved that he can hack it Sandra gets the same treatment. As Sandra is still limp and moaning from her climax, Tyler is finally allowed to jizz all over Julia's face and Sandra's parted thighs as a sign that he has done an excellent job. Julia has one last lesson for Sandra as she teaches the raven haired coed how to snowball her lover's cum.