A soft bouncy ass is as attractive to me as a soft bouncy stomach: not at all. I prefer asses to be like the stomach; hard and muscular.
I've posted a bunch in this thread but not all of them fit my ideal. The 3rd one on Jul 29, 2013 where the guy is kneeling on a bed is an example of what I find attractive. The one below that, in the shower, is also nice.http://www.realjock.com/gayforums/3312016