Sonic and his brother Mochi were found at approximately 4.5-5 weeks old, about 18 weeks now. Sonic has always comfort suckled but refuses to be satisfied with anything I've tried to give him. For a while he would suckle on his brother's penis and I had to separate them during unsupervised time. He seems to have grown out of that a few weeks back but now I've noticed him for the first time suckling on himself. I am very worried about this behavior because he is incessant and will go on for an hour or longer. If its relevant their neuters are scheduled for November.