I recently ordered a vibrator online that came with Ben Wa balls, i was curious about them after reading 50 Shades (who wasn't). Has anyone else used them? When I put them in, they don't fall out or really feel like much. I've walked around with them in, and they stay put with much ease. I tried working out (squats), walking up stairs, and I can still hardly feel them. I do feel a fullness, but nothing. Does this mean I need to get bigger or heavier ones? FYI I am 21 years old, 120 lbs. The ones I got are silicone, and tethered.