If the stepdaughter is already interested in these pictures and videos, then her pussy is ready to be used for its intended purpose. And the stepfather has more right to her than anyone else. He catches a glimpse of her getting a high from his cock, sucking vigorously and greedily. Twisting her around and putting her upright - the man drives the bolt all the way up to her balls. Such a stepdaughter in the house is a godsend. Let her work hard to strengthen the family.
If a chick offers to tie you up, her main desire is to fuck your mouth with her pussy. She's only interested in your dick because she's not interested. And even if you cum, she won't suck it. So the blonde just humiliates the guy by squirting in his mouth.