[simplicity 1370] The novice is back, need some advice Sewing Machines Parts and Sales in Los Angeles

I’m very bottom heavy, just to put that out there.

I’m trying to figure out how I should alter these shorts to work best with me. My dilemma is the big issue that my thighs likes to eat the crotch of my shorts. And the material bunches up in weird and unflattering ways. Here’s an album of my issues so you can see what I mean

If I wear the shorts higher up on my body (which I’m fine with), I have this huge gap in the waistband in the back, but the material doesn’t bunch up as much in my crotch.

If I wear the shorts a bit lower, there’s no back-gap, but the material bunches.

Which would be easier to fix? Reducing the back-gap? Or the crotch area? I know that I can’t completely get rid of my thighs eating the material, I’m just trying to find a way to reduce how bad it gets, lol

I don’t know how to do either, so if there’s any tutorials on how to troubleshoot, just let me know the words to google.

Thanks for any help and advice!