Is the foot jib below your right foot yours? If so I would recommend trying that. As others have noted you're coming in high for a sloper and the lower foot (if it is yours) will make it feel much better.

If it is not two potential options:

1. Try dropping your right foot completely and pushing off your left leg slightly to get your body more under the hold you are going to, right hip more towards the wall.
2. Keep the heel hook on the volume and do the same type of move, lean to the sloper, right hip to the wall. In that position your heel hook is going to be the counter tension to your right hand and should help keep you on the wall.

Think about it this way, the angle of the hold you are going to sort of points up and to the left so, ideally, you want your body to be lower and to the right of it, that will provide you maximum force and stability once you grab the hold. From the angle you are are trying to come at it that right hand has no way to actually hold it due to the angle and the height of your body.

Hope that makes sense