Help with shorts/jeans alternative... for a lycra virgin

I can't do the mtb shorts + kneewarmers thing. I don't shave my legs, so the kneewarmers end up sliding down and bunching over my knee. They're fine with cycling shorts, due to the extra gripper (of the shorts) holding them in place.

I suppose I need some sort of garter belt. No-one else would know, and I could feel all deviant and sexy whilst commuting.

I would know, I tell when you are being a sexual deviant, I know the signs.