Yeah, agree. I think sometimes it's better if there is some kind of reason behind it (ie. wrestling, role playing) other than just for the hell of it.

Some of the best times for me are when my girlfriend and I are in bed and we're mucking about arguing over who's stronger. We'll then wrestle for a bit before she either knees me or grabs me by the balls until I submit (or we're so turned on we can't help but just have to have sex!).