Unknown to them, Tank was watching them covertly through his apartment window. To his shock, he watched as P.L. turned into Chris, one of his neighbors, and P.L.'s feisty friend Natalie turned into a much more conservative version of herself. He then listened in on their conversation, as they talked about what to do about their situation.
Now that Tank knew about Chris and Natalie's transforming "ability", he was now affected by Narayanne's power as well. But maybe not in the same way as either Natalie or Chris.
He backed away from his window, shaking his head. He must have just imagined what happened to P.L. and Natalie, right? What he saw just wasn't possible. In fact, he probably just dreamed up the whole thing. Both of those girls were so vigorous and totally insatiable. So much so that Tank actually found himself getting exhausted and had to ask them to leave. Sure, it was the best sex of his life, but they were really pushing him to his limits. Maybe they could hook up later.
Meanwhile, Chris went back to his apartment, deciding to stay home for as long as possible, and Natalie drove home, trying to think up a lie to tell her husband.