The beginning on the couch reminds me of when I went over to tutor this girl in math while in college. I knocked on the door and she said it's open, come on in. After I came in, she said, please lock the door, I don't want us to be distrubed. I walked back into the living area and she was sitting on the couch with her legs up, fingering her pussy. She said she had to have some fun before we started talking math. I dropped my jeans, and she said "bring that rod to me" and we fucked for over an hour before we decided I did need to teach her some math. After the math session, she wanted to fuck some more, so we did.
When she gets on top, it's as though he is more concentrated on figuring out how saggy her tits are than getting off on her pussy. Look at the expression on his face.. it's like his mind is saying "holy shit, look at these saggy tits bouncing in front of me. What happens if I put my hand here? Damn, they are bouncing everywhere....meh."