How to tell when my baby is done eating

My baby is 7 weeks old and is exclusively breastfeeding. He had some trouble gaining weight at first but is doing well now. I do have a fast let down but he’s usually fine with it. However I have a really hard time telling when he’s full. He’ll come off and then want to go right back on. He comes on a off a bunch. He’ll finally come off and not want to see to go back on so we try to do the “play” time. After play time he has to eat again before he can go to sleep. Im just having a lot of trouble knowing when he is done eating. Sometimes he’ll have two or three ounces of a bottle and still want to feed. Any advice?