I came up with a drill for BJJ one Saturday when I was working out Rizan, one of my BJJ training partners and one of the best people to work out with ever. It involves very simply, just rolling for 3 or 4 minutes with your eyes closed. This is done at about 50% resistance or even less if you haven't warmed up
The rationale behind this is that most times, we rely too much on our sight when we roll, and yet, unlike tennis or football where eyesight is paramount, the close proximity inherent in Jits should mean that there should likewise be a lesser dependance on the sense of sight and more on touch.
Thus, I believed that by relying what we see, we tended to take in too much information, more than what we needed to roll effectively and efficiently. Take a blind person crossing the room, he or she doesn't have the luxury of wandering around like a sighted person - the aim is to get to the other side safely and efficiently as every step taken frivolously could mean danger.
Now I am not saying that you have there is no room to play in Jits,; not at all. My point is that you don't realise how inefficient your rolling in in terms of physical exertion and breathing expanded until you are made aware of it. And I believe that purposely handicapping yourself is a good way of opening this kind of awareness
Don't take my word for it..try it!