I agree, it isn't necessarily the weight, but the hair. Tenny can have problems back there. He is pretty long haired. You know what I do? I groom him, and wait until he gets really relaxed. Then, I use smaller scissors, and cut the hair back there. He doesn't even know I am doing it, cause he is used to me petting him, grooming him, and I just snip, snip, snip away. Even shorter hair is better. Tho, I have had him shaved back there, too.