Madeline/Hamptons totes on shoulder

I have a hamptons medium carryall and it when I put it on my shoulder one of the handles always slips off. I can't have it hanging right under my arm, so I have to kind of push it behind my arm. When it starts bothering me I carry it in the crook of my arm.
 
That's the thing about the Madeline, the straps aren't connected to the bag w/ hoops or hardware, they are sewn onto the bag, and they can't really slip off, unless the whole bag slips off of your shoulder. But with the weight of my stuff in the bag, it hasn't been slipping yet.
 
I have the Hamptons Leather Embossed Flap in Red. I usually wear the handles crossed-over on my shoulder and they stay on my shoulders OK. But if I didn't cross-over the straps, one strap will tend to slip at times.
 
I have a Hamptons Carryall and right now the handles are a bit stiff so it seems like the one might slip off occasionally, but once it's broken in it should be more comfortable.
 
I have a Hamptons Carryall in medium - if I cross the straps over then they don't slip off, but if I don't then the outside one tends to come off. I carry all my bags on my arm for the most part, so it doesn't really bug me.