She does.

You bounce along on Dina's ass. You can feel the jiggly sensation as you fall onto her. Her ass seems bigger than yours with her cock between her cheeks. You suspect she would still be even without, despite her small size. What she lacks in chest size, she makes up for in her lower body. Even though you are nearly fucking her whole length with each rise, you lean backwards so your ass is flexing less. This will help you jiggle more...why should she have all of the fun? She is rising harder than you anyways, so you let her do most of the work. After all, you are the one taking her massively thick cock up your ass! You go on like this for an hour at least. You are just so excited that you don't really pay attention to the clock. If Dina didn't mind the mess, you would rub yourself off. You are so horny you think it would only take a moment to get yourself off.
"Are you ready? I feel like I'm gonna cum again!" Dina ramps up her speed.
"About time! I can barely feel my bottom!" She didn't even wait for your answer. Halfway through your response you felt her cock jerk hard. Hot cum again jets into you. It feels great to have a second helping.
When her cock is no longer jerking hard inside of you, you pull up and off while making sure to hold the log upright. Once again you bend over to clean her.
"Ooh...you are so good to me! You get me all horny again each time you do that though," Dina tells you as you make loud slurping and sucking noises.
"That's good," you reply, "I'd hate to think you'd get bored so easily!"
"No, I have a lot more fun things we can do!"