I am a size 1 in jeans, and size 1 fits me well. EXCEPT for under my derrière.. They always bunch up right under my bottom, but every where else fits very nice and snug. It doesn't matter if its skinny jeans, jeggings, or 'boyfriend' jeans, they all seem to bunch up under my tush. Please, someone answer if you know why this happens? I'm sure my butt looks unappealing when this happens, and I'd just like to understand the cause and if I actually am in the wrong size? Thank you!!!