My evil arm drags to full mount combos. Nowadays I start in butterfly, with either an over or under grip and do the classic sweep. If it fails I grab the same side knee with my hook in the same side, outside and keep the person close, especially the arm. Start the armdrag sweep combo.
If my butterfly sweep worked, it's because i remembered to grab the right arm, so I finish with a knee cross into kesa and work for a stepover mount then do my double attack armbar crosschoke and eventually get the back for a bow and arrow.
In defense I spend time getting the double ankle or tripod sweeps and blocking pass attempts. I get into trouble when I defend a pass poorly and the person knows how to attack from turtle. If she doesn't, i usually recover butterfly and restart my sequence.