Try to wait it out.

I figured I'd just let my erection shrink away here in the restroom, try to regain composure, and go back to the table and hope Lauren doesn't try to go any further with me. I walked over to the sink and looked in the mirror -- my jeans were tenting out. Crap, I guess I'll just walk it off. I splashed my face with some cold water and paced around the bathroom for a while. I managed to push all thoughts of sex and Lauren out of my mind as I paced, somehow. I felt my hardness receding after I washed my face and hands with some cold water again. Good, finally, I felt like I could go back to the table.