You're right, it should be lower, down by your clit. Any higher and it'll give you an awkward-looking bulge that'll make you look constantly aroused. I think the problem may be with your sock holder - I'm assuming it's attached to your body with just a band around your waist. I tried using something similar to that once, and it always rode up. I've given up on that, and now either use a regular jock strap or just place it in a pair of briefs, either directly against my body or in the pocket of the briefs. It shouldn't move around much then.