I'm so glad you're back from college! My step-son is not here right now, but come in, I have something to tell you.
Do you remember how before you left for college, we had sex.
Well, I have to tell you that I'm pregnant with your baby! Look at my huge belly! Does that turn you on?
How about you jerk off on my pregnant belly and the fact that I'm pregnant with your baby!
Or maybe we can fuck?