Enjoyable.
I found that I liked the game. It's simplistic, but fun enough. I do have a few gripes, though.
First of all, breaking is difficult and essential. When I'm able to pull it off, races are much easier. When I can't pull it off, I lose -- Usually. Breaking with the down arrow key is hard for me. I'd recommend adding more keys available to use. Maybe the space bar as well as the down arrow key for breaking?
The sex could also use some work. It's a pain in the ass(No pun intended) to get anything more than a BJ. It would be nice if you added some sort of chain bonus that doubles(And then maybe triples) her pleasure each time you get in a "Perfect" rhythm. By "Perfect," I mean each time you hit the arrow key so that the meter flashes. This would make it easier and faster, but it would still remain a challenge, as you have to be good enough to get into that perfect rhythm.