Yes Kegels. I can move my dick and balls. I think you will find many who can do this.I do it, but couldn't begin to tell you how. Do you do any Kegels? The muscles are associated with the same ones you contract when you do kegels.
It's fun to do it when someone is looking at my bulge and I know they're trying not to be obvious.
Does anyone know how you can voluntarily contract your balls up towards your body? I have seen this in a few gay pornos (Aiden Shaw is good at doing this) and in a few vids on this site. Most guys' nuts contract involuntarily as they get close to cumming...